In my interest group (we'll be petitioning on SUNDAY!), I'm the only non white member. The rest of them are predominantly Jewish and are very close. I think that because they are a clique--don't get offended--this particular group is---that may scare some people off. I have a friend who is a a very conservative Jew who quit the APO group because he was turned off by the people in it.
There are a few non Jewish members in the group that I do get along with. I don't really get along with a few of the girls for personal reasons, and I feel as if I don't have any common bond with them as a liberal black agnostic nonconformist.

I've tried to talk to some of my friends to check it out, but they think it's a "nerd club"
It's not like there's only 5% minorities here either, but there are many cultural and ethnic based cliques that prevent people from reaching out to a new group.