I'm not going to go into SimplyCosmic-like essays with tons of links here, but there is quite some scientific proof that beautiful people are more succesful in life than "ugly" people. Although person might be more enthusiastic in "checking out" potential sexual partners than others, we all do it.
Evolutionary Psychology is the science that tries to explain human behaviour by looking at the principles of the Theory of Evolution. Beautiful people look healthier, and thus are more suitable for reproduction.
Looks are the
first thing we can judge. And we do. Of course a girl can turn out to be a fine reproductive partner (because she's sweet, or has humour, or is intelligent) later on, but there's always the first step of judging the looks of a potential partner.
I'm not saying we're totally controlled by this urge to approach only beautiful people; after all we are not mere animals. So I'm not saying Deeps is entirely wrong (not that it matters, since he left anyway), but there is no single doubt he's checking out (maybe subconsciously) potential sexual partners.