When you try to force ideological conformity with censorship, you end up creating even tighter echo chambers that amplify groupthink and entrench the very ideas you are trying to combat.
The best way to defeat an idea is to publicly tolerate and dispute it.
Twitter becoming a fascist cess pit has not reduced the power of fascists. Hearing even a completely ridiculous idea (like "the moon is made of cheese") told in a joking manner leads people to think it is more plausible than they otherwise would: https://en.wikipedia.org/wiki/Illusory_truth_effect Deplatforming is effective at reducing radicalization: https://www-cs.stanford.edu/~diyiy/docs/jhaver-2021-deplatfo...
Note that the thing that drove Andreessen to the right was left-wing thinkers who thought censoring anti-racism was bad: he was already pro-racism and pro-censorship before he created the group chats.
The problem here seems to be the income inequality & the power of money to win elections that give the uber-rich their disproportionate power.