I recently watched a series on UKTV History called Nazi Collaborators, which as the name describes was about those who helped the Nazis rule much of Europe and carry out the "Final Solution".
Some of these were people just trying to preserve their own people as best they could; if saying no cost you your life, you might well have to say yes. Others though were out-and-out evil people trying to gain personal power, like the Arjas Kommando in Lithuania. Many of these will burn in hell for their actions.
The details of The Holocaust are staggering. I had a look at the transcripts of the Nuremberg War Crimes Tribunal the other day; where graphic descriptions of the brutality carried out by the Nazis are present. It was also pointed out that much of the evidence used to convict the senior Nazis of crimes against humanity was of their own making; including the film footage we often see. People who film their "comrades" committing mass murder - words honestly fail. One Nazi even managed to work out an "efficient" way of mass burial to make the job easier. The whole thing was done on an industrial scale and with industrial methods.
I'm not even going to attempt to rationalise the collective mania that gripped Germany in the 1930s and 1940s. You just can't.
At the end of the day, we are all human beings. Sadly many people still forget that.
You can light a virtual candle here.