It is not as simple as that though. We know from war and concentration camps how many people 'just follow orders'.
Briefly...
In WW2 the Nazis learned from the Soviets that mass graves were a bad thing if discovered. They also knew that the Final Solution was an actual crime, the leaders acknowledged this but deemed the crime to be necessary for the survival of their own imaginably 'Aryan' race. Hence they got the Sonderkommando Jews to exhume mass graves and to build huge funeral pyres that they then used to burn the bodies. The Sonderkommando guys just followed orders until they were expected to build one final funeral pyre after all of the bodies were burned. By then they twigged that they were expected to meet their own fate that way. Only then, at the last chance, did they try to do something, e.g. try and escape or sabotage the gig. So long as there was someone in front of them in the queue these poor souls could be forced to do the unthinkable.
The Germans had it all worked out, they could get people to shove their own mother into the gas chamber. They had enough bullets to make this fully possible. They could get practically anyone to participate in the criminal venture. Even if life was a misery in the concentration camp they could get people to want to stay there another day because life under such circumstances was better than being actually dead.
I am certain in my own mind that everyone I have ever met in my entire life could be made into a Sonderkommando if push came to shove. This includes people in my family so quite a claim.
I am also sure that everyone I have met has heard of the holocaust. Yet I do not imagine any heroics of the Schindlers List type of Hollywood movie.
On the other hand, most regular soldiers do not like killing people, even if they are engaged in an 'honest war' and not a known crime. Some soldiers deliberately miss. Some go AWOL. Some play football with the enemy on Christmas Day.
But then you have situations like Abu Ghraig where atrocities happen but the people involved do not believe they are committing a crime and have no fear of being found out. These people really do have a psychological problem, they are actually 'sick in the head'.
However, during wartime the overwhelming majority of the population are not on the front line or anywhere near. Due to fear, propaganda and circumstance (e.g. being a parent, being too young, being too old) this bystander population passively goes along with the war, even if they do not fully subscribe to the doctrine of the day. These people have no skin in the game, they mostly support the doctrine and they don't think that far outside of what they are told to think, even if they laugh at some of the lies told to them. When the likes of MLK talk of being alone, it is these bystander folk that hurt the most.