Agree that you need a well designed protocol, but I think for small social, we're drowning in good protocols. A lot of the issues with ActivityPub, for example, come about because of socializing In the Large. Once you're just hanging out in a community it doesn't matter if someone trips and bans you or deletes all your messages; this is par-for-the-course for small social drama. What makes AP so fraught for large scale social is that small social drama affects the network as a whole. AP is just one example. IRC, XMPP, Matrix, mailing lists, they've all been working for years even decades.

I think you need someone to build out a good UX more than anything else. They who builds the UX will win the spoils IMO. There's plenty of protocol prior art to bolt on underneath the fact.