That doesn’t answer the point I’m making. If the instance your account was made on explodes, YOU lose your social graph, wether some of your posts survive cached elsewhere is not relevant, your account is gone, and so are your connections.
You have no way to prove an account made after the original instance went down belongs to someone, that’s the issue with federated systems.
As for content moderation, in nostr relay operators such as nostr.build handle legal takedowns on a daily basis, SSB is a little trickier since it’s mostly p2p but pubs are still able to control what flows through them to some degree.
the web, which also gets referred to as decentralized, suffers from the same proof problem. we have identity tied largely to dns. web sites can claim whatever. somewhere a line was drawn to indicate what matters most is creating something without a single point of failure?