Sadly it's quite common in the human population.

> What’s normal about bigotry?

uh I don't know, try asking almost any person who was born pre-1960? Doubt they all had brain damage. Not that it was necessarily a good thing, but it was certainly 'normal' in many eras throughout time.

> try asking almost any person who was born pre-1960? Doubt they all had brain damage.

Actually, they probably did.

https://en.wikipedia.org/wiki/Tetraethyllead

Leaded fuel existed for a few short decades. Bigotry and tribalism have existed since time immemorial.

Sure. But those born from the 1920s to the 1970s got a touch of brain damage, as a treat.

There's some very, very rich irony in your comment.

Pattern matching is very much a defining trait for humans.