It is certainly more nuanced and complex than reducing it in terms of a persons's propensity towards good and evil. You must look into the psychosocial conditions that made Germany the breeding grounds for Nazism. Why was it appealing to the ordinary Germany citizen? I recommend reading Erich Fromm's book Escape from Freedom as he explores this at depth. Still a relevant book almost 80 years after being written — where might observe similar phenomena today?