Different opinions of genocide

During a recent discussion amongst friends (because my friends are a group of the cheeriest people), one person brought up that they had met a former Nazi. In response, another member of the group stated that if they had ever met a former Nazi, they would "completely go off on them" (which I imagine means yell at them or be some type of aggressor). This got me wondering how many different people view the Nazi party, especially upon reading Browning and Goldhagen. I've come across two different responses, incredible anger, or an attempt to understand why. Through this class, I have become more sympathetic to the mindset of being forced into a situation where you have to kill or be killed. It makes me wonder what I would do in this situation - if I were given a root or reason to justify a certain group of people, and if I knew the "entire country" and my leader was on my side of the hatred, would I go along with constant acts of murder to the extent where it led to genocide? And what if I didn't agree and my life and family were threatened? Then would I agree to killing one or two people, if it meant I would be safe? I understand why many people would immediately assume that every member of the Nazi party wanted to kill every other person that wasn't of the Aryan race, and therefore nearly every person on the planet would have a grudge against them and would want to express their rage. However, what many people don't understand is the kind of situation that many of the Nazis were forced into in an effort to clear Germany (and Poland, and eventually all of Europe, etc) of every "minority". Again, I'm not defending or empathizing with the Nazi party, I am just trying to understand their situations.