I first became a vegetarian when I was nine, in response to an argument made by a radical babysitter. My great change - which lasted a couple of weeks - was based on the very simple instinct that it's wrong to kill animals for food.
I think I'm sort of blind to genre. As long as it has a sort of honesty about it, which I think you'll hear in whatever music you respond to, then I think it doesn't need to be called anything particularly.