Those are some mean girls! Most girls I know Love curly haired guys.
As for the other way around. I don't think I've ever had anyone insult my hair. Sure they've called it big. But it is...esp. before I discovered the right products for it. Most guys I know like to play with the curls. And I know I like tossing them. And hey...if my hair gets messed up cuz a guy was running their hands through it....well...give me an elastic and problem solved.
Maybe they think curly girls are more protective of their hair because of all we do to it (the perception of preparation that is) so they don't want to touch it for fear we'll freak on them? I don't know just a random theory that popped into my head.