Whether you know someone or not does not modify the danger of buying or selling cryptocurrencies. The various dangers involved are present regardless with whom you transact. For peer to peer transactions the most important thing is operational history. On that note, you are better off dealing with a very reputable trader than with your friends or family. You are confusing relationship with reputation.
I don't recommend buying Bitcoin from vendor's or p2p agents outside an exchange because only God's knows where they got those bitcoin from, it could be some stolen bitcoin that has been tracked down for a while and the next thing you just mistakenly bought them and send it to an exchange or any platform with your KYC in it, it would take long before the agencies track down and reveal you as a scammer for having part in the stolen crypto.
Your advice is terrible. A lot of the world is trading peer to peer
or OTC every day. Were it not for P2P things, we would not even have Bitcoin to begin with. Stop recommending centralized services that are leading us to a totalitarian nightmare.