Earlier quoted context omitted.
It might make sense behind the scenes, but was it a mistake for them to actually tell their users about it? They must have known the uglies would find out about it, so you've gotta balance out the fact that you've just flattered some of your users with the fact that you've insulted the rest. Besides, ugly users are probably a lot more profitable than good-looking ones.
Cutting the userbase sharply in half, with ugly on one side and attractive on the other, is probably a bad way for them to explain it to people. They'd be better off saying something like "we show you other users based on how much you have in common, including age, interests, attractiveness, personality, etc."
We know they run statistics all the time from their blog, so they probably saw something like 90% of active users are in the top 50% and saw it as a way to flatter them and keep them engaged with the site.