For real?
I get the cult thing is a major turnoff, but he's a great actor and his movies are mostly enjoyable.
He was great in A Few Good Men, The Firm, Born on the Fourth of July and Jerry Maguire.
His best role ever was the cameo as Les Grossman in Tropic Thunder.
I don't think he ruins movies because he is very charismatic and the camera loves him, but I don't think he is a great actor. He essentially plays the same character in every movie he has been in.
Keanu Reeves--he doesn't necessarily ruin movies, but I it always feels like any movie he is that is any good was a lost opportunity to cast with someone with better acting skills.
Hayden Christensen--I am not sure I have seen anything else he has been in, but he made the Star Wars prequels worse with his terrible acting.
Kevin Costner--He is fine when he is allowed to be himself as in Bull Durham, Field of Dreams, and for the most part, Dances With Wolves. But any time he tries to act at all, he is really bad.