@universeness
On the atheism of the Nazis, there seem to be roughly two positions from the capital "A" Atheists here: (a) National Socialism was a religious movement; and (b) National Socialism was not an atheist movement, shown by the fact that it was happy sometimes to use religion to gain and maintain power.
Position (a) can't really be taken seriously, but position (b) (which seems to be where
@universeness is coming from) is usually just a defence against those militant theists who claim that atheism is inherently evil. I think (b) is fair enough. The Nazis emerged from a still quite religious milieu, which most of them did not care enough about to give it much thought for or against, thus they were neither religious nor atheist in general, and there was probably a diversity of opinion among Nazis on the issue.
But some leftist atheists during and just after the war came to believe that there was something in the secularized culture of modern Europe that allowed totalitarianism to happen. European antisemitism at the time of the Nazis had become scientific in character (it was
pseudo-scientific, of course). It took up the older
religious tradition of antisemitism and ran with it in a racialist direction, so it was motivated and justified differently than it had been in previous centuries. So some pessimistic atheist social theorists blamed the very historical evolution of which the
loss of religion's social importance was a central feature. From this point of view, it is something in the process of secularization that led to totalitarianism and genocide (the instrumentalization of reason and all that). In other words, religion was being lost, and without anything to take its place, bad things happen.
This seemed to be further supported by the existence of another of the world’s most brutal and totalitarian regimes, one which was atheist and which engaged in the persecution of religion, namely Stalin's government of the Soviet Union.
Me, I certainly wouldn’t say that atheism or secularism necessarily result in totalitarianism. The minimal point I suppose is that society can end up in oppression, war, and violence whether it’s religious or not, and therefore that these evils have other causes. The idea that it's all caused by religion is no better than a conspiracy theory.