I think it's funny how often Slate Star and its associated groups come so close to Marxist theory while dancing around the edge of it and this article is no different:

Are these tribes based on geography? Are they based on race, ethnic origin, religion, IQ, what TV channels you watched as a kid? I don’t know.

What could it be? Maybe some common sort of... substantial situations? :curious-marx: no that's not quite it

EDIT: Also immediately after that he implies it's genetic :michael-laugh: