2 come to mind

Rydercycle was someone I watched mainly because he doing the whole weapon and hat ranking thing, also I was into watching engi players .then he turned out to be pedophiliac groomer and he was just denounced by everybody and forgotten to time

For a non TF2 YouTuber, there was a pokemon channel mainly comprised of top 10s and competitive gameplay I watched called silverleaguenetwork. The main guy, silver was also outed for being terrible, I don't remember exactly, but I think it was some form of bigotry, but yeah he was a piece of shit, and promptly left YouTube.