You make a great point, there's a big temptation to commit narrative fallacy when trying to explain narrative fallacy.

So we should look for empirical evidence.

At the same time brains are complicated, psychology is complicated, genetics is complicated.

We know a lot about all of the above but we don't really understand any of them.

The history of all three sciences is full of narrative fallacies.

Given what we don't know, absolute proof, especially in genetics, isn't currently possible. So we have to settle for the best working explanation based on what we know. I think there is plenty of peer reviewed support for the idea that we are biologically inclined to look for neat explanations so that we can file challenging concepts away as resolved and focus our bandwidth on other things.