Religious instructions and commandments wouldn’t need to exist if they weren’t trying to reign in basic human nature. We don’t need commandments to eat or defecate because our human nature already compels us to do that.
Which means the capacity for evil is part of our basic nature. Humans have a compelling instinct to form groups. And they have a strong instinct to fight with other groups. It makes sense from a survival perspective. If your land is going to be invaded by outsiders, how will you get strong enough to fight them off? You’ll do it by splitting up into your own factions within your country and warring with each other, weeding out the weak and making the survivors stronger. Then, if evolutionary theory holds, the offspring of the survivors will all be stronger than the ones who didn’t survive.
Human beings who didn’t have this instinct would have been wiped out by invading tribes long ago and removed from the gene pool. We carry the genes of the ones that were not wiped out into today.
People have the ability to form into separate groups on almost any basis whatsoever. Geography, national identity, religion, politics, race, schools, or even competing sports teams. That versatility is a sign of how powerful the instinct is. A group is defined as much by who is left out as who is let in.
So there isn’t a great mystery to why Hitler did what he did. Wars have been fought for millenia because we are instinctually driven to fight them. The way in which we decide to split into groups of “us” and “them” is fairly insignificant. Almost anything can be used as a reason.
“..exist if they weren’t trying to reign in basic human nature...”
Ah, the philosophical argument is where does human nature come from??
And is there an Absolute Moral Law?