It means it's not the style they want, and it's not bad enough to make fun of. XD

Or it could mean that she doesn't have superstar looks. In pop music, being beautiful is nearly as important as having a great voice.

It makes me so angry when Simon favors certain people because they look better. I get really frustrated, and would love to just smack him!

There have been tons of amazing singers that are either overweight or have some other "problem" and they get turned down because of it. It kind of sucks, because it's all marketing. Except for Susan Boyle on Britain's Got Talent, perhaps, because she is truly astounding.