Maybe ISPs is an okay comparison? Most of us are on different ISPs but we access the same internet.
It's probably more productive to just ignore the technical details. Half the country seems to believe they're buying "wi-fi" nowadays.
Just stick with "try Mastodon" or "try Lemmy" and let the non-technical folk build whatever mental model suits them best.
Forget the forensics guys, if he keeps this up they'll be prepping the rubber hose and dentistry tools guys.