What reality are we in?! The name of the thing literally contradicts the term. You are using a HOSTING PROVIDER. Somebody other than yourself is providing the hosting!
If I use my old laptop to host stuff is fine. What if I live in an apartment building and a good neighbor has a big server and let's other poeple use it and host stuff on it. I have my own vm, etc. Does that count as self-hosting? I would say yes. What if I rent bare metal from a provider?
In my view self-hosting doesn't end at the boundary of my apartment.
As I said previously, everything comes down to trust. If I don't want to run my stack on someone else's computer because I don't know if they will be a good s steward of my data that's valid, and I should own my own hardware.