The problem is that the mainstream is simply declaring historical events one way and any other dissenting viewpoint or evidence is suppressed. And there IS evidence.
The fascists (and Putin's propaganda trolls) have been successful in disruption any dialogue between people from the actual left: socialists. Not the neoliberal "democrats".
And now you do their work for them: You censor the socialists (marxist-leninist, maoists) because some "dirtbag left" troll once was mean to someone. You probably can't even link to an example of what you accuse entire group of. But this tankie slur gets repeated and amplified more and more. People simply call you tankie, downvote and everyone piles on without thinking.
The problem is that disinformation and post-truth doublethink on the so called "left" (=neoliberals) is almost indistinguishable from MAGA like OP.
If you check out lemmy from an instance that hasn't defederated from the socialist instances you'll see that basically half of lemmy activity is invisible - the socialist half. The result is rather predictable.
Thanks, really interesting analysis! I'd argue that profit seeking is significant in this change though. Polarizing content leads to anger and higher engagement. So any algorithm that is written or trained to increase profit from advertisement will encourage that outcome.
I believe there are other influences too, the fascists and putin trolls (agitprop) has led to some "automatic downvote and ban reflex". On lemmy the mods are basically power tripping non stop in trying to curate their fief into a single minded community that brooks no dissent. There is one narrative and anyone dissenting is a . On all sides, people are just sick of the bullshit and are on a hair trigger.
This seems to the be result of the last decade of mainstream media and social media being run for profit through engagement. I have no idea of how to reverse this.