The only thing I’m certain of is that I am confused...

Doesn't it always just come down to us vs them? It's pack mentality, it builds stronger bonds with those on your side and justifies your own qualities or perspectives that you'd rather not look too closely at. We all have examples of this in our own lives but tend to be blind to our own faults.

The sort of adaptive intelligence it takes to over come this entirely is probably reserved for machine thinking. Our biology will always lead us astray somewhere down the line.

I'm no psychologist though.

Because it's easy, if you accept without question, life is generally much easier. l

Well I'm no psychologist, but there are quite a few theories like confirmation bias, attribution bias, and several other systems of thinking that lead a person to their strong beliefs. Before there was the science behind psychology, Sir Francis Bacon wrote in the Novum Organum that human beings are prone to four idols of the mind, mostly being , identity, upbringing, and false teaching. Very good book to read, It really changed my life and the way I observe the world and the human condition.

It's scale...if you are dealing with a few people you can look at all sides and compromise...if you are dealing in billions you can't consider all options. Most "black and white" people don't apply that in their personal interactions...only to simplify a world view into an arguable point

It's easier for the human brain to understand a dichotomy then I truly dynamic situation the ability to say this is good or this is bad is easier than saying this has some good marriage and some bad merits etc