"Crapper" as slang for a toilet has an attestation from before Thomas Crapper was a plumber, so if that's what you were referring to, then it's also not a case where it was named after the guy.
So poor Thomas was a victim of nominative determinism?
Mostly. He made significant improvements to the toilet (they already existed). And his last name was then forever destined be the butt (...) of jokes.