I suspect that Maher's progressive opinions and positions have not changed greatly over the past 5+ years. I don't claim to have researched that by going back over 5 + year old shows and comparing to recent year(s). Rather the Democrats have moved significantly more to the left of the political spectrum, making it appear that he used to be more progressive. It is indisputable that the Republicans have shifted far more to the extreme right than average Dems to the left. What hasn't changed with Maher is that he hates political correctness and BS and isn't afraid to point to examples of them on the left. The advent of social justice warriors trying to burn those not genuflecting to their opinions at the stake have given Maher a bigger supply of both to speak out against.
Maher and Bill Kristol would both laugh out loud to hear that some now consider them to be fellow travelers!
Bill donated a million of his own money to Obama campaign in 2012, then another million for Democrat Senate campaigns last year.
To the best of my knowledge Kristol did not. There are a number of former Republicans who have left the party as it has moved farther and farther to the right and now into Trump cultists or cynics who cynics who care more about staying in power than honoring their oaths of office. My question for them is why do they think the cancer now threatening our 250 year republic developed in the Republican right rather than the left?
In answer to your last question, 25 years of history. The left has its problems. Too much political correctness can be argued to be one of them. The left has extremists and loons. I've known some personally. AOC is very left of center, but has substance to her arguments. However a fair bit of the nutty left love her too.
Until 2018 the extreme left had virtually no voice on the political landscape in the US. There were a few on city councils here and there, but Bernie was about the most liberal figure on the national stage and he's a bit to the right of some of the newer voices on the stage. I don't have a problem with extreme positions that are well thought out. While I don't think we should adopt them whole hog without serious consideration, this is where new ideas that eventually become accepted start such as women's suffrage and same sex marriage. An evolving culture should always be exploring new ideas with an eye towards improving.
While having a few extreme voices in a legislature is not a bad idea, it's a bad idea to have them in positions of power where they have widespread control over many parts of the government. For one thing radical changes almost always stir deep resistance and can lead to civil war.
The one exception is radical changes in a time of crisis accepted by everyone. Then the new radical leader is accepted with less resistance, but it can badly damage the country's fabric. In the aftermath of 9/11 the Bush administration made some radical moves that were popular at the time, but ended up eroding the stability of the world as well as the US. The invasion of Iraq was a major blunder, but it was popular at the time (I spoke up with my concerns, but was shouted down). The Patriot Act has many parts that are unconstitutional that have given the government unprecedented ability to spy on us all.
Similarly FDR took advantage of the chaos of the Great Depression to bring in large changes in the US. Some have remained popular such as social security. FDR also got a lot of resistance to his attempts to pack the courts and his running for 4 terms was outrageous enough they passed a constitutional amendment to put in term limits.
The moves of the Bush and FDR administrations were small beans compared to some of the other moves in history. The Nazis in Germany made the conflict between communists and Nazis worse and then proposed the Nazi solution to the crisis. They broke a constitutional democracy in the process. The communists in Russia seized control when the people had gotten fed up with the tsar. Napoleon came to power in the chaos following the French revolution. Other dictators have come to power in other countries by settling chaos either of their making, or just general chaos.
Over the last 39 years in the US, the Republican party has been the one setting the tone for the culture. Between 1932 and 1979 it was the Democratic New Deal language that framed all political debate. Look at how Eisenhower or Nixon governed. They were to the left of Clinton and Obama much of the time because they had to mold their message to the backdrop of the time.
The memes that have dominated US politics since the Reagan era are tickle down economics and self determination. Trickle down economics has been a disaster for around 80% of Americans and only been a real benefit for about 0.1%. The left has found self determination to be a two edged sword and have been successful in pushing through some new ideas like legalizing cannabis and same sex marriage on these arguments.
To a large degree Democrats have been on the defensive, having to mold their ideas to the Republican memes that dominate. The two Democratic presidents over the last 39 years have been moderates compared to New Deal era Democrats because they had to.
Not only have Republicans controlled the memes, they have also had dramatic control over a fair chunk of the media. When the FCC was established int he 30s by FDR, they started a Fairness Doctrine that require broadcast outlets to have balanced political coverage. Something similar still exists in the UK and Canada.
Reagan put in a new FCC chief who ended the Fairness Doctrine. Congress felt string enough to pass a law putting it back, but Bush vetoed it in 1989. The FCC also had strict rules about radio and TV station ownership. Ownership was limited to only a handful of stations per person or company. In many cities the local media was owned by locals much like car dealerships were. Stations would often be affiliated with one of the big three networks (NBC, CBS, or ABC) and would play their programming, but would also show their own programming, sometimes syndicated programs and sometimes home grown programs.
The new FCC loosened the ownership requirements so one entity could own many stations coast to coast. There were some wealthy conservatives who went on a buying spree and bought up radio and TV channels in just about every market in the country. AM radio was dying, so these stations were a bargained and got scooped up in large numbers. These new owners started conservative talk radio networks. Rush Limbaugh was the most popular, but there were many other conservatives filling the air waves with conservative talk.
The left tried to fight back. The most notable network was Air America which folded in 6 years because it couldn't compete with the deep pocket conservative networks, even in liberal media markets.
Through most US history, the two parties were like fans of sports teams. Yankee and Red Sox fans would talk trash about one another, but at the end of the day both loved baseball and had more in common than differences. Bipartisan legislation was common because at the end of the day members of both parties recognized they needed to work together and didn't usually have serious problems with the other side beyond political differences.
Conservative talk radio cast Democrats as not just "wrong", but evil. Many times they used terms that would stir up emotions in very conservative religious listeners. Another thing they did was constantly attack the rest of the news media for having a liberal bias.
Soon Republican politics started taking on this "liberals are evil" meme. Newt Gingrich came out of nowhere to seize control of the House by exploiting a weakness in House rules as well as CSPAN policy.
The House allows any member to address the chamber when not in session. Before Gingrich nobody ever did it because why speak to an empty room? But Gingrich realized that CSPAN would always cover whatever was going on on the House floor, especially in the middle of the night when nothing else was going on. So Gingrich started making speeches in the middle of the night to the CSPAN audience and he crafted his speeches to hit on memes going on with talk radio at that time.
Insomniacs started watching Gingrich and he rose to prominence. His speeches started getting air time during the day too. He created the Contract with America and got a slate of like minded Republicans elected. Gingrich overreached impeaching Clinton, but he left his mark.
At the same time things were moving right in Congress, the news media outside of conservative talk radio was feeling the pressure of being called overly liberal and they bent over backwards trying to be fair. This came to its absurd conclusion in the 2016 presidential campaign when they were unfairly harsh on Hillary Clinton and gave Trump massive bys for disqualifying behavior and history in an attempt to be balanced. But 2016 was just the extreme case, it's been happening since the 90s.
Getting the non-conservative media to change their coverage by yelling "liberal bias" at every turn crafted the idea in the public's minds that both sides were equally guilty when all this was orchestrated from one side. The Democrats don't have perfectly clean hands, they have fought back on occasion and like anyone who has been abused constantly for nearly 30 years they have some collective PTSD.
Starting Fox News in the late 90s and the online conservative media just continue the trend started with talk radio.
Another thing with this conservative slime machine is they are not adverse to making up stories and then turning them into big deals. The way these stories get going is some nutter out on conservative social media comes up with some crazy idea like Barack Obama is not really an American citizen, or Hillary Clinton is running a child sex ring out of the basement of a pizza parlor (with no basement) and it starts making the rounds within that world. Some of the less well known conservative media personalities pick it up and give it more voice, then the largest conservative media outlets pick it up initially talking about how "there are rumors online" about the story then the "rumors" bit gets dropped and it becomes gospel. Soon the rest of the media outside conservative circles is covering it too.
This is fueling a divide between the older part of the population and younger. For people who grew up before the online world existed, if a mass circulation paper, or radio or TV news covered a story, it was almost always well vetted and even if the story changed some over time, the core of the story was usually factual. When older people hear stories about Clinton running a child porn ring on a major news outlet, they believe it because they think it must be vetted.
For those who grew up in an online world, they are much more skeptical of anything they see online. Most have first hand experience of false stories showing up online. Many times about them spread by rivals at school. The downside is these generations are skeptical even when presented with provable facts too. They grew up with so much gas-lighting they doubt everything.
There is a big contrast between old school Democrats and the new young talent because the old school Democrats have been worn down with decades of constant attacks and like an abused spouse, they habitually walk on eggshells to avoid conflict. The new Democrats see the world differently. The only assaults they have ever gotten have been from people much older than they are and rather than seeing it as abuse from a peer, they see it as old men yelling at them to get off their lawn.
As for Bill Maher. I've watched Real Time off and on for years and his politics haven't changed much. I don't always agree with him, but I do value his contribution to the discussion. He is quick to point out silliness anywhere. That's part of his comedic schtick. When the Democrats were out in the wilderness, there wasn't much to lampoon there because they were playing defense most of the time. Now that liberalism is coming back, some bad ideas are evolving with it.
Maher still does standup and he does it in every part of the country, including very red states. He has seen things on the ground that most liberals haven't. He's been places no Democratic presidential nominee goes after the primaries are over. He has said many times the Democrats have America on policy. What the Democrats collectively agree about is pretty much what most Americans want too. Some are too ideologically blinkered to realize it, but many others like the ideas, but dislike some of the other trappings.
One thing Maher goes on about is overboard political correctness and I agree with him. Due to pressure from PC students many controversial speakers have been disinvited from speaking at universities. While I agree in many cases the people disinvited are loathsome people who should be mostly ignored, if you believe in the 1st Amendment they have a right to have their say and ultimately I think it's a good thing people are exposed to their ideas.
A culture is much stronger when a broad spectrum of ideas are available to all. There will be nutters who adhere to extremist ideas as a result, but the bulk of the population will be inoculated from extremist ideas by knowing what they really are. It's much harder to tar Nancy Pelosi with the label of radical liberal when she's clearly to the right of others in her caucus. The right wing media tries, but because people are seeing AOC out there, it's becoming a lot harder for the meme that all Democrats are radical ideologues to stick.
Some of the more PC things going on in the left is turning off people in the middle who would otherwise vote Democratic. Right wing media is amplifying these flaws, but they exist.
Add into the mix that over the last 35 years the Democrats have become very bad at politics (playing the political games), but excel at governing. Republicans, in their increasing ideology, have completely forgot how to govern, but are masters at playing politics. As a result, a lot of incompetent Republicans have risen into office and the Democrats have become overloaded with people who really know what they're doing. Rick Wilson has noted that the average Republican in congress today is a high school sports coach whereas the average Democrat is an attorney with serious experience in their resume. Every former prosecutor I can think of in Congress is a Democrat: Kamala Harris, Amy Klobachar, Adam Schiff, Eric Swalwell, Ted Lieu (JAG), and there are others I have forgotten.
There was a politician running for office years ago who put forward 12 legislative ideas he wanted to achieve. He said "if you agree with me on 8-10 of these, vote for me, if you agree on all 12, have your head examined!" He recognized that in politics it's very rare for any two people to completely agree about everything. I definitely take issue with Maher in many areas, but his politics have been consistent and he always is quick to attack what he sees as bad ideas. He's flawed, just like the rest of us and if you're brain is engaged, he'll tick you off sometimes. But I think he and others like him should be listened to. He has a perspective on Democratic politics from outside the bubble all political organizations can form around themselves if they aren't careful.
Both parties have some kind of bubble. For Democrats it's fairly thin and they are often willing to break the bubble when they become aware of it. The Republican have turned bubble thinking into a virtue and chastise any Republican who even acknowledges there is a world outside the bubble.