On some level all matter is chemical. Metal has been maligned with lots of stuff, but I've never heard that one.
I didn't like it at first either, and when I started to like it I went for the radio stuff (simply because it was available), like early Metallica. As I learned about more and more bands, I find very few of my favorites have much, if any, radio play. I guess my musical ear got more and more accustomed to heavier and faster stuff that before just sounded like noise.
How a person's tastes change through experience is interesting, but I think you're safe from addiction. It's been a few days since I've given my winamp list a run, and I'm not chemically jonesing for it