You have no excuse to not be beautiful because everything you can possibly want reasonably, is attainable.
So, to simplify. We have no excuse to not be beautiful because everything we could reasonably desire is attainable.
The problem that I see with your argument is that you asume that humans are always 100% rational creatures, which isn't true. Beneath the layers of reason that coath many of our experiences lies something far beyond the reach of our "reason".