Norms against flame wars and the old "don't feed the trolls" made for some really excellent experiences growing up on forums as a kid (and instructive experiences when I ignored that advice). It's too bad we weren't able to bring that energy to social media, because wow is the alternative depressing to behold.
Social media owners wanted all the benefits of superscale communities with none of the responsibilities - it isn't surprising that moderation got worse.
Reddit vaguely has a workable approach with subreddits, but it's still high variance, and they have to discourage long-lived comment threads.
