In my experience r/politics is the most biased and lopsided major subreddit on the entire platform. People criticize r/conservative but I genuinely do not see the same level of wanton hyperbole, demonization of the other side, and calls for revolution in r/conservative that I routinely see in the comments of major posts from r/politics.
Perhaps 80% of r/conservative threads can only be commented on by flaired users. Certainly all the threads one would actually want to contribute to at any rate. How do you get a flair? You have to post conservative-sounding things elsewhere or in the non-flair-only threads. Only once you've established that you're not going to deviate from the groupthink will you be allowed to participate in the community.
Conversely, r/politics is a free-for-all. Granted, there is clear downvote brigading on alternative opinions but they do not get taken down ever. HN is going to read your "intentionally one-sided" quip and not understand how correct you truly are.
So /r/politics is much better because instead of taking down "alternative opinions" they just downvote it? I am not convinced. Effectively downvoting alternative opinions not only effectively makes them completely hidden from view for most users (under a "this comment has too many downvotes" barrier), but the users who do stumble upon those massively downvoted "alternative opinion" comments will get a nice dopamine rush from seeing their own opinions further re-enforced because the downvotes must mean this opinion is wrong.
Both are insidious and both behaviors massively contribute to group think bubbles. I don't think the pattern of behavior of one is massively better and more healthy than the other.
Better than moderators doing it. Post something that deviates from what the moderators of r/conservative consider acceptable conservatism and they just ban you. If the community legitimately downvotes you, then at least you're facing garden variety groupthink instead of "my way or the highway" of a couple mods enforcing what is acceptable discussion.
This is a pattern. Trump, at his coyly named "Truth Social" bans more people than Twitter ever did. And not for violent threats, either, but for simply disagreeing with his narrative.
1. Cheering the liberal tears that must surely ensue, as 5th graders are taught how to shoot guns in class.
2. Fabricated Biden attack. Just, invented, like as if it was a funny thing to do, or as if there isn't real stuff to criticise him on.
3, 4. Pictures of tweets from Republicans, both blaming Biden/Dems for systemic issues (problems caused and maintained by both sides).
5. Outrage that Sunday morning shows aren't talking about the man on serious meds, who called Emergency Services saying he was going to kill Kavanaugh (for trying to loosen gun control regulations).
... Fucking. Crazy. That's not politics, it's not discussion; it's mental assault on morons. And you are not allowed to post or comment there without affirming your conservatism.