It seems like groupthink and herd mentality are at play, but what helps to make those things take place is this backfire affect. It’s like another piece of it.
Usually, I think of herd mentality as people wanting acceptance from peers and they are persuaded or manipulated by fear and greed. We definitely have some of that happening in America right now. Groupthink is more civilized I guess, but still a manipulation by peer pressure and wanting to fit in. The backfire effect and other confirmation biases help people rationalize staying with the group.
I always say people have a hard time changing their minds, because it can mean to them the sky is falling. Their whole world construct might get disrupted. Especially, if you tie religion in this can be very effective to keep people in place, but even without a formal religion, a set of beliefs about life, morality, good and bad, and right and wrong, most people need to keep that all in a perfect order or they get very uncomfortable or afraid.
I think people like ANef and I live in the grey thick line of life more than the black and white. The world seems plastic to me, meaning pliable. I’ve always moved between many groups of people not quite fitting in to one specific clique.
I’m not any sort of psychologist. This is my layman’s view of it.