Anna, I'm really sorry you're feeling so bad. I get it. I do. I never commented in Una's pretty thread, even though I've been following it from the beginning, and she posed such an interesting question. I had so many thoughts and reactions that each time I started to draft my own response, it got longer and longer until, finally, I didn't have the wherewithal to get it together. And by that point, I really didn't think anyone wanted to read what would have become a fairly pedantic essay-thing.
Pretty as a concept is *loaded*. Because, ultimately, you're right: I believe much of it is due to privilege or lack thereof and how we use language. I believe we look at it through a variety of socio-cultural lenses that include things like body image, relationships with our mothers *and* our fathers (or other caretakers), location we hail from (for example, just in the US, the NY metro area vs. the American South - in general, there's typically a different emphasis on pretty), education, age, race, ethnicity, class, and even political bent. And also, what we inherently look like and our experiences of romantic/sexual relationships.
I can imagine that there were a few (or more than a few) responses that made you feel crappy. If I weren't as inured to it as I am now, I would be feeling crappy, too. For what it's worth - and I'm not trying to make excuses or diminish how you feel - lots of people aren't used to scrutinizing their own reactions in these ways.
It would be pretty boring if we were all exactly the same. It wouldn't be the same here without you and your lovely, smart different-ness. Of course, you know what's best for you, and you should do whatever you need to, but I hope you'll be able to come back. xoxo