A soldier is bound by oath to do their duty, the contention is where does that duty end and conscience begin?
There is a logic towards shooting 'cowards', I'm not defending it, when faced with the fear of an imminent death, the notion of a certain one is sure to gird one's loin.
It is only when you read into the atrocities of this era that you begin to understand it's vicious cruelty, men dancing in front of the soon to be killed previous owner of a coat, guards stealing the belongings of the dead, profiteers swapping a loaf for diamond, even when you look at places like France you see the nature of what happened.
France was loathe to 'evacuate' it's French Jews, but was willing to give up it's foreign Jews, so, the gendarmes rounded up the French Jews and sent them to transit camps in France (run by them) to be processed and sent to the east.
In camps like Drancy the children were separated from their parents, they bore the scratches as they were dragged from their parent's arms, the gendarmes even rounded up 40 prisoners to be held hostage and executed in retaliation in 1941.
If memory serves only 1 French civilian has been tried for a war crime, anyone guilty of such crimes should not be allowed to live out their days with even the thinnest veil of respectabity.