There are a few things you need to realize first before tackling the whole why do the majority of women like assholes question.
1. Really awesome and cool people (both boys and girls) are uncommon and even rare by definition.
2. Whatever you find in abundance, lots of girls who like assholes for example, must not be that awesome or cool.
Now for why so many girls like assholes...
The same reason so many guys like women who they can protect, guide, order around, and more often than not abuse. Guys like that need to have their egos fed, and having a girl to protect and possess is what feeds their egos. Girls often need to have their egos fed too, but they are taught to express their egos not thru domination, but thru submission. When a girl meets nice guy, he's just a nice guy, she had nothing to do with it as far as she can tell. She didn't MAKE HIM into a nice guy. But when a girl meets an asshole, an asshole who is interested in her, she starts feeling like she has power over him, that she can MAKE HIM be nice to her, and that feeds her ego and makes her feel affirmed and top of the world.
Most people are like that, which is why MOST people are not awesome and cool, they are just self-absorbed.
I hope that helped, and I hope you have some luck meeting people who are not MOST people (though you might have to wait till college or after college, hehe).