Most Helpful Guy
Obviously the guys you're talking about see qualities they find attractive in these girls that you're not seeing.
Not knowing the specifics about the people you're referring to, I can tell you that I will always go for the girl some people might consider "a 7, a 6 or a 5" that I have chemistry with and who is genuine, guileless, warm, open, intelligent, funny, etc, over a "9" or "10" who is narcissistic, shallow, materialistic, fickle and high-maintenance.
Of course, all factors being held equal, I would likely be more attracted to the more classically beautiful girl. But generally speaking, you rarely find a situation where all factors are equal.2