feel like your last paragraph there is a pretty good argument against centralised, top-down net censorship though (since that's what facebook et al already do) - having rules + moderation be entirely alienated from the communities they run means that both the users feel no empathy towards them and the mods can't learn how to deal with specific issues in specific communities. Can't really figure out how I actually feel about Ao3's attitude, obviously posting nonce shit is bad but also rules around sexual content have always been primarily weaponised against LGBTQ folks on the web and there's a hell of a lot of grey zone between wholesome and Evil