One of the ideas I should have expressed more clearly was how the distinctness of the Nazi Holocaust fits in within human history. It is unique in its set of circumstances and will never be exactly duplicated, but it was a unique symptom of a general human social tendency. I am still not exactly sure what the best way is to phrase it. Like you say, these people who perpetrated these acts were “normal.” The social structure that created that normalcy is not that unusual in human history. I think what most concerns me is that saying “never again” to the Nazi Holocaust didn’t work because people tacitly assumed it couldn’t happen again, when it has always been far too easy for it to do so and still is.