Comment by notatoad

the pseudo-anonymous amateur communties still exist. but they're private and invite-only, because a public community that allows anonymous posting becomes a cesspit of toxic behaviour, or else requires so much content moderation that the only feasible way to do it is automated recommendation algorithms. (invite-only phpbb forums of old still exist, but the modern equivalent invite-only community is the group chat)

without the threat of "we'll kick you out and you'll never be able to get back in", these sort of communities don't work. there's just too many assholes on the internet now.