Because it for some reason is the only kind of music that really "clicks" with me. Alt rock is too soft and mellow for me and hip hop is simply not my cup of tea (not to mention, I can't relate to "black culture" at all). Country is too happy and corny for me, and most punk and hardcore is too emo-ish for me. There was a time many years ago when harcore/metalcore was my favorite genre (I had been a deathmetal head previously), but now I decided that I like real metal better, with death metal, black metal, doom metal, and thrash being my favorite genres. I still like some hardcore bands, and a few punk bands, but I'm pretty much a metalhead.