I've often wondered if this is because so many men in prison were abused (sexually, emotionally, physically) as children, and have tons of stored-up hate for their own abusers, so when they get a convicted child abuser in their midst, they go for the jugular, heaping abuse on one they know is guilty, as a vicarious way of venting rage at their own abusers.
I never really thought about it that way, but it does make perfect sense.