I agree. If the topic comes up again, I'd honestly tell her, of course they'd tell you that, they want to get into your pants.
That should make her think twice.
Or you could take the nicer route and just say something like, well, it takes all types, and all types are beautiful in their own way.You prefer your own straight hair for yourself, obviously and I prefer my curls. I wouldn't trade my curls for anything. I'm glad I have a BF who agrees so it doesn't really matter to me what some random guy in bar thinks.