For me it's just the fact that people have delved so deep into their echo chambers that they've lost all sense of what regular people think. Like I'm fine with someone being an extreme communist, they can have that opinion, but it seems like a lot of people on here talk to other extreme communists so much that they think more nuanced communists are somehow right wing. It doesn't matter how much you try to concede to acknowledge their viewpoint, their personal Overton windows have shifted so far that they exclude everyone but people exactly like them, and it just makes conversations impossible.