There are some absurd claims for various things out there. Claims that things that can't exist are real based on spurious evidence. But the argument you outline above actually does hold together if you look at it from the angle. It is a fact that the Israelis did move back into the area after being gone for 2000 years. That looks like colonization to some.
The history of the state of Israel from 1947 had a phase where they were scrabbling to hold off other states from overrunning them. At that time they were the underdog. Boomers and GenX grew up with that. By the time the Millennials came along, Israel had the upper hand and they were fighting an insurgency.
Most people are terrible at history that happened before they were born. To a lot of people if they didn't experience it, it didn't really happen. They may accept it happened, but abstractions have a degree of unreality to them.
I am not one of those people and I struggle to grok that way of experiencing the world, but I've seen it many times.
From all I've seen Biden and the bulk of elected Democrats know that supporting Israel is important. There are a few who disagree, but the bulk believe in supporting Israel. There are also quite a few who believe the Palestinians need humanitarian aid.
There are other cases this is from 2015
The 27 politicians who raised the most money — and still lost
Jeb Bush raised over $100 million and went nowhere.
Political affiliation changes less than people think. Pew did a study on who was president when a cohort turned 18 tended to predict which party they voted for the rest of their lives. A fairly popular president would win over a majority of that cohort for life. An unpopular president would swing that cohort to the other party. Not talking about all here, just a majority of the cohort.
If you don't think contributions matter to DC politicians, then you don't know how the cake is made.
I didn't say anything about people changing party affiliation. You can shift in your beliefs without changing parties.
Jews were not gone from Israel for 2000 years. There have been Jews living there for millenia. Here's a little refresher course for you: