This is a common, but disingenuous, objection. People also don’t make their own electricity. Is therefore “self-host” an unreachable goal, which nobody can fulfill in practice? No, this would be a useless definition.

I agree that that's a bad definition, that's my point. The question is how _you_ are defining it since your definition seems to have this problem; if you're going to complain about others' use of the term you should indicate what you think the term should mean!

It's not disingenuous. Being autistic about language use is honorable when the distinction you are trying to preserve is actually valuable. It's less so when the differences aren't that big in practice because in both cases you have a lot control over the services you run but in the end are still somewhat dependent on third parties.