> Someone I follow posts something I think is intelligent and polite, and the replies are filled with people launching tangential attacks and making weird accusations.
You can still curate this experience. There are accounts that I will never read the replies from, and there are accounts that I know will have great replies.
There are other accounts where I will. I ban, mute, and use the "don't show retweets from this user" feature liberally.
> suppose hoards of people with political opinions you detest start creating accounts that pose as "your side", using the worst possible arguments for your positions, insulting everyone, and making "your side" look stupid and cruel. Is that a kind of speech you want to protect?
If you're talking about the NPC accounts, they are clearly satire by their tweeting style and avatar.
Actual subversive impersonation is tricky, but I would hope that those kinds of accounts get outed by the side of the people they are subverting and the side they are subverting can condemn those arguments, positions, and tactics.