Perhaps ActivityPub is struggling because it tries to be too much. If it does well at being Twitter, why must it also be Signal messenger? I don't use DM's much at Twitter, if that feature wasn't a part of AP/Mastodon, I wouldn't cry!
That comes across in delete requests. There's no way to guarantee that a server would honor that request. I don't think a blockchain style solution is needed -- just don't try to offer things that are impossible to offer. (There's this idea that AP/decentralized will be Nazi-free... what a ludicrous promise! Although, perhaps that's more an expectation of the users than the protocol authors...)
That comes across in delete requests. There's no way to guarantee that a server would honor that request. I don't think a blockchain style solution is needed -- just don't try to offer things that are impossible to offer. (There's this idea that AP/decentralized will be Nazi-free... what a ludicrous promise! Although, perhaps that's more an expectation of the users than the protocol authors...)