My friend has an American roommate who has inexplicable habits and I keep telling him, "It's because she's an American."
Americans are taught that it is every person for themselves, that dog-eat-dog and might makes right are the gold standard of ethics and morality.
And as you likely know, in schools kids undergo regular "active shooter" drills, drills which so far have had no success in saving kids from death, but certainly help to keep them frightened at all times.
No child should grow up under such sad circumstances, and many Americans realize this without understanding the big picture.