No one in the west understands how the Germans became Nazis or how the Arabs and many other Muslims and even western Muslims become cold blooded Nazis with the sole preoccupation of murdering men women and children including their own – they kill more of their fellow Muslims that don’t follow their barbarism than they do Jews and Christians (think Iraq, Pakistan and the Middle East.)
The answer has nothing to do with religion – the Nazis weren’t overly religious – rather it has to do with perception.
You see you and I (hopefully) perceive a good world; as such we love what we perceive, I love you for I perceive you to be good, you love me for you perceive me to be good. True we may have different philosophies, worldviews, religions but that is because we where raised in different environments, if I was raised in your society and you were raised in mine, you and I would both share the exact same worldviews that we both have, rather they would be reversed.
So what causes good people – for people are not born evil – to become Nazis, cold blooded passionately focused only on murdering others.
Freud had to analyze this and he came up with a controversial but perhaps correct theory that within us we have an instinct for life and an instinct for death.
Perhaps a similar way to explain this, is we have what we love and what we hate.
We love goodness and kindness for we intrinsically are social beings not anti social beings while we hate malevolence evil dissension strife disunity.
However a person who is very ill tastes sweet foods as bitter, similarly with enough beatings, humiliation and lack of respect necessary for the perception of goodness in humanity a bitter person emerges who actually percieves the world as a genuinely hostile place.
This individual hates the world and now his perception is reversed, people are evil and hence should be eliminated.
This is why they even kill themselves in the process (hitler must have know even albeit subconsciously that his war of murder would end in his own death which he cowardly took before the allies got to him as Bin Laden and certainly the homicide bombers are doing.)