That is because 90% of the girls are just slaves to their own lust. Sakura, Ino, Karin and all of those other pathetic fan girls just "like" Sasuke because of the subjective and superficial concept of looks. Physical attraction is caused by the same hormones that generate lust. That means that you are being a weak minded slave if you "like" someone because of their looks. You're weak minded because you don't even have the strength to control yourself and resist your own hormones. You should like someone because of their personality.
This is why I like Hinata and Tenten the best out of the Konoha 11 girls. We all know that Hinata likes Naruto and we know her reasons. Not once has Naruto's looks been mentioned as one of those reasons! Tenten's interests are unknown, but at least she doesn't seem to be a pathetic Sasuke fan girl! Hinata and Tenten ftw!
P.S. I'm not saying that it is wrong to like Sasuke. It is just wrong to like him (or anyone else) for things like appearance or his arrogance.