In Internet 90% of the people are "above average" in attractiveness. Either you are not that good looking as you think you are or you are very modest scratching the untruthfulness. Very attractive people tend to value MORE not less physical appearance, which it makes senss, due to assortative mating and the worldview they grew up with.
No, I believe vain, insecure people post lots of photos of themselves online. Many of them compensate for their ugliness by clothes, background and makeup. Most beautiful people that are busily secure in their lives don't have the time to post 10 times a day!!!!
No, I mean good-looking people tend to care a LOT more about their appearance than regular people. Not only their appearance but the appearance of their partners. Being good looking is part of their identity and has shaped their worldview.
Same reason smart people value intelligence a lot, rich people value money, and so on and so forth.