Simple: what else do you listen to other than metal?
Me, I listen pretty much exclusively to metal, but once in awhile I listen to classic rock and other hard rock stuff. I used to listen to jazz music and was a very good saxophone player back in high school. I kind of grew tired of it though. I never really listened to rap or pop, somehow completely avoided that.
EDIT: I had to remove the first draft of the poll with one vote, so please vote again. The title was horribly confusing due to a rewrite and I could not edit it due to it having one vote already so I had to do a new one and remove the old version.