I think we have pounded on MB enough here..
Mea culpa, might have been a tad unnecessary harsh.
Racism is a form of tribalism, but there is a pretty big difference in holding to racist ideology and acting racist. Everybody sometimes do the later, even if they are not ideologically racist.A better discussion would be to consider the differences and misinterpretations of political and cultural terms for today. To my mind racism is a form of tribalism, such as we see in the American political and cultural wars ongoing today.