You also need to mention the Bulgarians and the Danes who saved their Jews.
My opinion about the people who acquiesed with the Germans is that we can't be too judgemental - we could have easily done the same in their place -- read "hanns and Rudolf" - it talks about Rudolf who was theAuschwitz camp director who came up with the idea of gas chambers. The account is chilling - he was not a monster, he just took one little step towards evil, then another, then another - each time the step was justified by what had happened before
It is the slippery slope to hell. horrifying in the pscyhologic analysis -- these were NOT monsters, not demons, but human beings like us -- we need to constantly be on our guard not to slip even a little bit, or if we do, to correct ourselves immediately.
The rationale for the gas chambers was simple: The units that were killing Jews by shooting them were exhibiting all kinds of mental issues as a result.