Music Babble

I agree that it's horror, but I see people argue that that type of stuff isn't horror, but those arguments only occur in context of film. If it was a written story nobody would dispute it.
Even Jonathan Rosenbaum said something like "Val Lewton made noirish art films that people only think of as horror movies because the studios decided to market them that way." That's a paraphrase from memory, but I'm pretty confident that it's close enough.

After I watched the Paul Schrader Exorcist prequel, I read a bunch of reviews of it and a number of them said that it wasn't really a horror movie, even though it is a movie about a priest battling a demonic possession.

FWIW, I've never seen Rapture. I have seen Basket Case quite a few times though.