Indeed, it does appear to make you believe things which everybody should know from experience are false. Attractiveness standards are not "arbitrary", however much you might want to believe it. We have slightly different preferences when it comes to physical attractiveness, but the differences are fairly minor. And attractiveness norms don't need any "reinforcing", they seem to be pretty damn-near hardwired in our genomes.
I suppose that makes sense: if she were completely hideous she'd know about it, but if she's so-so in appearance then she's more likely to be offended by her non-inclusion in the top half.
Reading this, I expected the author to be a trollish blob, but clicking on her name reveals she's nothing awful: http://bitchmagazine.org/sites/default/files/imagecache/prof...
I suppose that makes sense: if she were completely hideous she'd know about it, but if she's so-so in appearance then she's more likely to be offended by her non-inclusion in the top half.