Ok, you are wrong
(well, the dilution is kind of a thing- though a bit more complex since it's mostly diluting the shares the hostile takeover person owns.... as everyone ELSE gets the chance to buy new shares at a discount but that person does not- but I mean wrong on the vote part).
As a few folks have mentioned, twitters articles of incorporation include surprisingly broad powers for the board to fight takeover attempts [B}without[/B] any shareholder approval needed.... one of the reasons it's called out in the articles filed with the SEC is so a potential investor is aware the board has such powers available and can act without their (the shareholders) approval on these matters in certain ways and that can inform their decision to invest in that company or not.
As another example- the board can (without approval from anyone) issue a bunch of preferred shares, with whatever voting rights they specify, as a measure to block a takeover. (this is not unique to twitter and is sometimes called a Blank Check Preferred Stock defense) where they say issue X shares of this stock and each share gets 1000 votes instead of the 1 vote a common share gets.
The idea there's a political bias has been pretty thoroughly debunked- not just by the reddit CEO but lots of examples of folks of both leanings making censorship claims... and not just on this specific platform. It's not "political speech" that's banned- it's wildly out of bounds behavior that happens to include political speech.
They do have a fiduciary responsibility, but it'd be up to courts, usually after the fact, to determine if the measures they took, within the allowed bounds of their granted powers, were in the financial interests of shareholders or not.
It's not nearly as simple as "Elon offers more than the current price, so if they don't take it the shareholders got shafted"-- if it was that simple
every takeover bid above current price would have to get approved and that's not remotely the case.
So any anti-takeover measure they take- from rejecting the offer, to poison pills, to the blank check thing I mention, and more- is a balancing act on their part regarding what they CAN legally do up front to block the takeover (which is a
lot) versus what they believe they could successfully defend in court after the fact as not violating their fiduciary responsibilities.