Stanley Milgram, a well known Social Psychologist, did some tests on how people respond to directives (obey) from perceived authorities. It was frightening the high percentage of people who distance their own personal responsibility from something when an "authority figure" tells them what to do.
Neuroscience teaches us that the development of brain tissue in the frontal cortices (etc) is virtually free, so a human can always decide differently. But I reckon your argument because sociology gives out true results on a broader scale and that's why these insights are extensively used by advertising corpse or other kinds of mass media manipulation. Persons of special interests, you name it.
Humans can be immensely shaped by their upbringing so that's why it is important not to damage their brains by maltreatment/abuse and nourish empathy and humane values. Some of the stuff that's happened was obviously downright evil just by judging by the feeling you get when you only see copies of the actual death. This is an emotional responce that can be observed even in higher evolvedf animals, e.g. wolfpacks or rats, they fight hard for their group status but when the loser signals defeat the attacker stops and in most of the times, aggression isn't deadly and serves a positive social function.
But we know already that there are humans (psychopaths and sadists) which have a certain part of their brain not really developed, the neurons there are less connected and seeing on an REM less active. Experiments suggest these people feel no empathy for their kind. Empathy prevents extreme situations alone.
For example Hitler was in a state of constant toxic psychosis because he became politoxic addicted from all the stimulants he took before speeches. Then he had parkinson = actual brain tisssue damage. Totally unfit to be a leader of anything in all regard!
In the case of World War II atrocities to Jews, the authority training which allowed the atrocities, can be traced to Kaiser Wilhelm and his public schools training programs (indoctrination, obedience training). He didn't want thinkers, he wanted obedient soldiers and workers.
There's even much more to it a longlasting christian antisemitism simply out of religious and/or political reasons as this stuff is intertwined throughout the last 2000 years.
Jews fell prey for Hitler's political play to create a picture of a common enemy and by so, ally the rest. He knew the european history very well and understood the tragic dynamic central europe had taken since the 1000 year old reich. His deceivings fell on fertile grounds and he sacrificed countless millions as collateral damage in his granddelusional quest for power & domination. Because... he has no empathy, and not even sympathy for his own kind, like the incidents of his last days at the Führerbunker in Berlin confess.
A normal person with a healthy brain would never consider such a method in the first place, they would be horrified from themselves. It's something you can get a glimpse of when you awake horrified from a nightmare when you stabbed someone to death or so.
It's completely unnatural to do so and serves absolutely no positive biological or evolutionairy function and neither makes sense under a capitalistic attitude.
Science also more & more unravels that we have more & more neurotoxins in our environment and that the number of psychological diseases is increasingly mounting. The longlasting damage alcohol does to a fetus brain is mindblowing.
en.wikipedia.org