It works because I decide.
There's no intrinsical limitation on the number of participants
Don't you like what a user says?
You can ignore them
Don't you like what some instance does, you can block it.
Any platform that is popular has an editorial board and doesn't want you to say things they don't like.
Simple as that.
Newspaper had no comments sections because it's silly to comment the news, they already decide what to publish and what not.
They already chose who to talk to, there's no point in discussing when you can only comment what someone else wants you to talk about.
Have you seen today on HN a post about exactly 40 years ago, when an Italian civil plane, the Itavia Flight 870, was shot down by a fight between NATO and Libyan fighter jets and 81 innocent people died?
You won't, because it's gonna be flagged as politics.
But you're going to read about every cat fight between über rich silicon valley founders because that's not politics for them, it's what they wanna talk about.
Trolling is a problem for the platform, not for the users.
I don't mind trolls, if I can decide who they are and silence them.
If they do it for me, it's censorship.
Censorship is not bad per se, but it's not done in my name, it's only in the platform's interests.
Do platforms ever ask users what do they think about banning someone?
Of course they don't...