I think girls are attracted to "bad" boys because of the 'ability to protect'.
Most females want a male who can protect them and their children or just them. It's like some kind of natural thing with men, since they are naturally stronger than women. When a man shows a sense of fear in something than that woman usually doesn't give him the attention. Why the hell do you think that most women want you to stand up for them? It's her test to see if you can show your manhood.
It's all about protecting your mate, but then again, there are those girls that can fend for themselves.