I don't really understand it, either.
I have a good friend who is a life-long 'conservative republican', to the point that he really believes whatever the conservative republican spin machine tells him to believe regarding social issues, politics, and economics. I mean he believes it immediately, automatically, and fully. And he believes he believes it, himself, when I can see as plain as day that he believes it simply because he's being told to believe by this group that he has so intently identified himself with.
I suspect there are some very deep psychological reasons involving his childhood that have something to do with it. But even still, I suspect I would have reacted very differently to those same circumstances. So maybe it's just been written into his DNA. He was coded to be a 'follower' and he just can't help himself. I am certain that he has no idea that he's doing this. And he would be very insulted if I even suggested it to him.
I don't understand it. But it seems I am seeing more and more of this 'self-identification by external group-think' these days because the media has figured out that this tendency exists in people and can easily be exploited to it's own advantage. As have the republican party. And so they are both exploiting it to their maximum effect and there are apparently a lot of people who are susceptible to it, for whatever reason. But don't bother trying to tell them about it, because they will not hear you, and they will become very insulted by your even suggesting it.