"Why Do Girls Like Jerks?"
The right question:
"What does [girl I am interested in] like in a guy?"
Are you attracted to girls based solely on how "nice" or "jerky" they seem? Why would they be then?
You don't even have to stop being a misogynist to recognize girls evaluate men in more than one dimension. Even a shallow girl looks for more than one thing. What about looks? Money? Fame? Penis size? Any of those could be higher on the checklist than "nice/jerk." And every girl is different.
For example, I like a guy who is smart, sarcastic and good at video games. (Hey, I can open my own jars but I can't get past the Meat Circus level of Psychonauts on my own.)
OK, OK ... I couldn't even get past Black Velvetopia.
One of my friends used to have a thing for blue eyes, and another needed to find a guy that shared her musical talent. And on the other end of the spectrum, I've had friends that just need to check for a penis and they're good.
Being nice is important to us, but it's not a free ticket to the bedroom if you've got none of the other things.