The problem with these sorts of affinity arises when you use ingroups to get economic leverage over others. And whether that's culture or ethnic inclusiveness, when and if it happens, is a whole big bundle of possible problems.

That could happen, but that isn't necessarily what I'm talking about. I'm talking about being polite to non-Jews but being friendly to Jews. And I think that's the way most people are about their own ethnic or cultural group.