from Milton Mayer's 1955 book, They Thought They Were Free.

That's a good quote. I hadn't read it before.
I'd like to take a moment to plug Milton Mayer's 1955 book, They Thought They Were Free. It's an excellent account (woven from a series of interviews) of the thought processes and various complicities of average Nazis in the 1930s.
My favorite passage from it:

"...Each act, each occasion, is worse than the last, but only a little worse. You wait for the next and the next. You wait for one great shocking occasion, thinking that others, when such a shock comes, will join with you in resisting somehow. You don't want to act, or even talk, alone; you don't want to 'go out of your way to make trouble.' Why not?-Well, you are not in the habit of doing it. And it is not just fear, fear of standing alone, that restrains you; it is also genuine uncertainty. Uncertainty is a very important factor, and, instead of decreasing as time goes on, it grows. Outside, in the streets, in the general community, 'everyone' is happy. One hears no protest, and certainly sees none. You know, in France or Italy there would be slogans against the government painted on walls and fences; in Germany, outside the great cities, perhaps, there is not even this. In the university community, in your own community, you speak privately to your colleagues, some of whom certainly feel as you do; but what do they say? They say, 'It's not so bad' or 'You're seeing things' or 'You're an alarmist.'
And you are an alarmist. You are saying that this must lead to this, and you can't prove it. These are the beginnings, yes; but how do you know for sure when you don't know the end, and how do you know, or even surmise, the end? On the one hand, your enemies, the law, the regime, the Party, intimidate you. On the other, your colleagues pooh-pooh you as pessimistic or even neurotic. You are left with your close friends, who are, naturally, people who have always thought as you have....
But the one great shocking occasion, when tens or hundreds or thousands will join with you, never comes. That's the difficulty. If the last and worst act of the whole regime had come immediately after the first and smallest, thousands, yes, millions would have been sufficiently shocked-if, let us say, the gassing of the Jews in '43 had come immediately after the 'German Firm' stickers on the windows of non-Jewish shops in '33. But of course this isn't the way it happens. In between come all the hundreds of little steps, some of them imperceptible, each of them preparing you not to be shocked by the next. Step C is not so much worse than Step B, and, if you did not make a stand at Step B, why should you at Step C? And so on to Step D.
And one day, too late, your principles, if you were ever sensible of them, all rush in upon you. The burden of self-deception has grown too heavy, and some minor incident, in my case my little boy, hardly more than a baby, saying 'Jewish swine,' collapses it all at once, and you see that everything, everything, has changed and changed completely under your nose. The world you live in-your nation, your people-is not the world you were born in at all. The forms are all there, all untouched, all reassuring, the houses, the shops, the jobs, the mealtimes, the visits, the concerts, the cinema, the holidays. But the spirit, which you never noticed because you made the lifelong mistake of identifying it with the forms, is changed. Now you live in a world of hate and fear, and the people who hate and fear do not even know it themselves; when everyone is transformed, no one is transformed. Now you live in a system which rules without responsibility even to God. The system itself could not have intended this in the beginning, but in order to sustain itself it was compelled to go all the way."
-Milton Mayer, They Thought They Were Free: The Germans 1933-1945