In history, we usually try to understand people and cultures. But unfortunatly, WWII and the Cold War are still pretty recent. during the cold war it was probably as important to demonize the Nazis as it was during WWII, and so it is politically incorrect still to look at the Nazis as anything other than Evil.
Usually I say that 'Evil' is a religious concept and plays no part in history... but as this is a religious forum, maybe that argument won't hold much sway. So maybe I should say that It is your Christian duty to try to understand and forgive people" (Its worth a try). An old solder who fought the nazis once gave me a peice of advice. He said that you should never hate your enemy, for if you do you will underestimate them, you should try to respect them, and by understanding them, you will defeat them.
So anyway, if you want an answer to this question, you should ask yourself who became Nazis, what motivated them to join this political ovement, what were the alternatives.
So imagine... you are from a family which is rich, well conected, and like your father and your grandfather before him, you join the military. Then the Nazis get into power.
You are well connected and you wish to stay that way, and in these days being well connected means being a party member. Besides, you abhore the communists and the Nazis are outspoken against them.
Do you see any problem so far?
You may say, there is a little problem about persecution of Jews. But in the 1930s, antisemitism was the norm. It wouldn't be something you would think twice about, especially if you believed half the things that the Nazis were telling you. And we do tend to believe what our leaders tell us, even in this day and age we find it hard to believe that our leaders might be lying.
I know a number of former Nazi officers... they seem like decent people to me, with one exception.
