At the time this was occurring, most were either unaware or willfully ignorant that mass extermination was the true goal. The core issue is not race nor ethnicity, but usury. The concept of charging interest on loans was introduced by Hebrews to the Pharoh as detailed in the Torah. The same issue has come up again and again throughout history. Consider for example the Saducees of the New Testament. They were essentially investment bankers, while the Pharisees were essentially lawyers and politicians. Fast forward to Nazi Germany, and look beneath the rhetoric and distortions, and what you will discover is that Hitler saw himself as a Christian hero saving Germany from the debt slavery of the so-called 'Jews.' It was a gross simplification, but the simple fact is, when you owe money to the bank or your landlord, particularly in hard times, you'd be inclined to look the other way if the government forced them into hard labor and forgave all your debts to them. Of course, if you continued to see them as human beings, as you should, and you were becoming aware of what was being done to them, you would do all you could to protect them without endangering yourself.
The answers I have given are harsh, but are grounded in fact. Now, with all that is happening in America, it is more important than ever to understand these things before history is allowed to repeat itself.