P2P social networks have a moderation problem. Individual users are all their own moderators, which works like the “block” feature on Lemmy and KBin. However, this can get super exhausting so fast. There’s only so much fascist, homophobic, or transphobic bullshit a person can tolerate in an online interaction before they just give up and leave the network because it feels like there’s nothing worthwhile there.
There may be a solution to this problem someday, but for now, you have a choice for P2P networks. You can give up on user discovery entirely, as in Secure Scuttlebutt, where your network grows as you get invited to follow people or invite people to follow you. Alternatively, you can give up on moderation entirely, as with Nostr. I think either are fatally flawed presently, making federated services the best choice for having good control over your social networking experience without having to do every single part of it yourself.