I think the us/them of race is much discussed, while other versions of us/them can creep in unexamined: http://slatestarcodex.com/2014/09/30/i-can-tolerate-any

I think the us/them of race is much discussed, while other versions of us/them can creep in unexamined: http://slatestarcodex.com/2014/09/30/i-can-tolerate-anything-except-the-outgroup/ http://slatestarcodex.com/2014/09/30/i-can-tolerate-anything...