The thing is, if a very pretty and beautiful girl puts up her picture *with the intention of 'fishing', intending to just collect compliments they don't need," then people get resentful. "You won the lottery, but you're going to ask me for money?" The idea is "You should already know you are top tier, so why are you asking others if you are?" It builds resentment.
Then, very few people want to be the person that tells an ugly person that they have the genetic curse of disfigurement. So they upgrade their rating, usually. I have noticed this is more common with females than males. It's basically a lazy "Ehhh, sure, you're attractive, but I'm only saying that because I don't want to be perceived as an asshole; and, I ultimately don't care one little bit about you, because if I did I would take the time to tell you the truth and what you could work on."
Then, there are many average chicks that look like an 7 or 8 or 9 with some makeup.
At the same time, men and women perceive attractiveness differently. Men are, scientifically, more likely to share opinions on how attractive a specific woman is; whereas, women are much more varying in how they perceive attraction--with men, anyway. I suspect it's the same for females. So while you might perceive a chick as ugly, a lot of guys might perceive her as banging hot.