The only major decentralized forms of social media that I'm aware of that have confronted philosophical questions of how handle moderation have been Mastodon, Bluesky, and arguably Lemmy.
I don't know of any sense in which Mastodon has increased centralization, I think its blocking tools have been distributed essentially since the beginning, not something that has iterated toward centralization over time in response to an unfolding debate. Although it does have a complicated history and as possible that new things have happened I'm not aware of.
BlueSky though, to your point, is a good example of centralization not being reliable in terms of not being accountable to users. Or for a different way of saying the same thing, the lack of accountability has served to reveal how centralized it truly is.
It does seem to be simple enough that people don't get confused about using it, but it doesn't seem to walk the actual walk of decentralization.
The big example that comes to my mind is Matrix, where most homeservers use Mjolnir to apply centralized public blocklists of other servers/people they don't like.
So if for example #archlinux disagrees with your opinion and they decide to ban you for it, you are now banned from many other unrelated channels.
I have also seen subreddits that auto-ban users that have ever posted in specific other (unrelated) subreddits.
Mjolnir is designed to apply decentralised public blocklists - i.e. you pick which banlists to apply; there are a bunch published by different people (matrix.org, the matrix 'community moderation effort', etc). Admittedly moderators do share lists (so that if #archlinux bans you, others might pick up the ban), but there's no intrinsic centralisation.
https://github.com/matrix-org/matrix-doc/blob/msc2313/propos... is how it works fwiw.
BlueSky also has this, but it works poorly because people use blocklists as a form of harassment, or else take over existing lists and add their enemies to it.
And bluesky has the ultimate power of choosing which blocklists to show you
Eh, not really. It really is decentralized, you can find them on Google. They could stop respecting a certain list but I think you can host your own AppView and get it back?
No one is successfully hosting their own AppView at this point. Blacksky had one but had to roll it back. Northsky has it as their priority, but they don't have one yet.
I mean when lists are opt-in and users have to specifically choose what lists to subscribe to then well… kinda tough shit if you end up on one that many people are happy with. That's the point of putting moderation in the hands of users, they're allowed to block you for any number of weird reasons.
It sucks when server operators group together because it effectively becomes a centralized moderation team that makes decisions for users with tenuous implicit consent but user moderation lists aren't that.
Not really, because there's only one AppView and you can't unsubscribe from the lists they dislike.
Wheras with Matrix, you can run your own server, with your own rules, and federate with the rest of the network.