If you are interested in the topic read - Ordinary Men: Reserve Police Battalion 101 and the Final Solution in Poland
> Christopher R. Browning’s shocking account of how a unit of average middle-aged Germans became the cold-blooded murderers of tens of thousands of Jews
https://www.goodreads.com/book/show/647492.Ordinary_Men
https://www.amazon.com/Ordinary-Men-Reserve-Battalion-Soluti...
> The first mass murder takes place in a Polish town called Jozefow. The commander of the unit was teary-eyed and choked up when he gave the order to his men. Accounts hold that he even gave them a way out, stating that if any man didn’t think they were up for the challenge (of murdering thousands of Jews on that day), they were free to step down. About twelve men (among hundreds) decided to step down and opt out of the killing.
> Ultimately, these bakers, salesmen, and police officers were directly responsible for the deaths of 38,000 men, women and children through mass-shootings, and another 45,200 through collecting people from the ghettos and forcing them onto trains for Treblinka (a Nazi extermination camp).
> Browning offers up a variety of reasons that these ordinary men participated in genocide, some more pertinent than others. Among those reasons are deference to authority, psychological need for conformity, fear of a brutal regime, fear of looking “weak” in front of other members of the battalion, detachment from the people they were killing, and indoctrination via the Nazi propaganda machine. None of these individual reasons would have been enough to drive ordinary men to mass murder, but altogether, the reasons became enough for many of them.
Also Masters of Death: The SS-Einsatzgruppen and the Invention of the Holocaust is a good detailed telling of logic of events that lead to invention of extermination camps (it was easier on the consience of Einsatztruppen)
https://www.goodreads.com/book/show/16891.Masters_of_Death
PS. Also reading president Weizsäcker's speech kep in mind that Germany and Austria actively opposed justice upon perpetrators of Holocaust and other war crimes in the East.