Hm, well, I don't know that I'd call those "tribes," and I (reasonably, I thought) interpreted "tribalism" to be ethnic or racial based on it appearing in a discussion of "Friends Are Genetically Similar."
Yeah, of course that is true, but I was making what I thought was a reasonable reading in context. It seems like the OP is describing something more like groups of friends; you can't really be a member of multiple tribes, necessarily.
