prevalence of greek life

Nobody really cares either way. Greeks do tend to dominate the social scene, and it's true that the overwhelming majority of social kids at this school either join greek life or are on a sports team that doesn't allow kids to pledge (i.e. lax, baseball, basketball), but nobody looks down on you just because you didn't join a frat/sorority.

Ppl, who think stereotypically, are usually not very bright. You are asking us to generalize, which is not too far from thinking in stereotypes. It is somewhat true that if a person is not on Hopkins' sport team and is not in Greek life he/she might get some condescending treatment. But it also depends on someone's personality. A nerd, or someone who is living in a comfort zone, while downplaying an importance of social skills, will be ignored or even disliked by the "Greeks". Fun and outgoing person will be accepted. However, it is true that Greek community is kind of closed circle and "Greeks" prefer to spend time with their own kind.