I've studied history. The Nazi party was to many, just a successful political body that was reclaiming Germanys lost glory, and forging a future for the betterment of its citizens. A large portion of their personel were unaware of concentration camps, and the crimes on humanity being committed. It wasn't until the last few years of the war where racial propaganda began to become intensely powerful. By that time, all the other propaganda had permeated into a strong enough subliminal force that they really could say "jews are thieves" and the designers knew that it would carry the desired effect.
The people put into posts in concentration camps... these are a unique case. They knew of the horrors, but could they do anything about it? Short of sacrafacing their own lives and commiting treason of the state (refusing to carry out their duty, desertion, releasing the prisoners), they were in a corner. They were given orders to operate these death factories. They were orders. They were trained to carry out orders. Where were they to do?
[sub] There is no easy answer. Even after years of study, reading accounts, and writing about these topics, there is NO "correct" answer. We may not realize it, but the same dilema exists in modern military; if your CO orders you to commit a morally questionable act in the name of your nation (shoot a child because someone thought he might maybe be carrying an explosive device), you the soldier can either carry out your orders, or put everyone at risk by disobeying them. Who is the criminal in either situation? There is no morally right answer. There never is. The only "right" answer comes from victors.[/sub]
If I knew this man, this reformed ex-nazi, and [em]I believed[/em] he was a good man, and he regretted his actions, yes, I would hide him.