I have three questions regarding self-hosted social networks: (1) Isn't it a huge advantage of social networks like Facebook that it's a central instance which

I have three questions regarding self-hosted social networks: (1) Isn't it a huge advantage of social networks like Facebook that it's a central instance which can remove accidentally leaked data from the network and which prevents data scraping on a large scale? (2) Isn't it also a disadvantage of peer-to-peer networks that when your key leaks, all your data that is stored in the distributed network will be irreversibly accessible to everyone? (3) To which degree is it feasible to burden the average user with crypto key management without a locksmith?