I'm badly attracted to someone I hate...why?

I understand where you're coming from...however, it's a bad idea. Infatuations, as in your case, are VERY strong at the start. Just ignore it, and it'll fade away with time. You're probably attracted to him because you find certain traits of his "arousing", that you may find repulsive publicly. Its very common..called the "Bad Boy complex" in women. If you can, try to build up a healthy relationship with him so you can get to know him better, but don't try anything out-of-line.