I'm exaggerating a bit to make a point (my actual view is slightly less Stark) that I think gets brushed off or overlooked too easily (but is important) I thin

I'm exaggerating a bit to make a point (my actual view is slightly less Stark) that I think gets brushed off or overlooked too easily (but is important) I think the reasons are more multivariate than a single psychological principle. But yes, in-groupism is a component I do think. But that is a component against the backdrop of societal and geographical sorting among a whole set of preferences and values e.g. (can predict a lot more about you if you are blue or red because we've all sorted ourselves) as an example of another component.