Genocide and the modern age

Long before the Holocaust, maybe even one million years ago, there was mass murder of humans by other humans. But the 20th century has witnessed more such murders than any other. The causes are little understood, but it is suggested Auschwitz is what may happen when you divorce morality from politics. An unsolved puzzle is how otherwise civilised individuals underwent the psychic numbing which made them conscienceless killers, cogs in the machinery of murder. To avoid recurrence, we must eliminate "structural violence."