The truth about the Third Reich
One might look back on Nazi Germany and wonder how a mighty regime which conquered most of Europe and started the greatest War and genocides in human history could be based on little more than pseudoscientific racialist quackery and conspiracy theories. It's completely irrational. But then one remembers that there was nothing rational about Nazism - it was a movement based on Hate, not Reason, which attracted supporters not through intelligent argument, but childish bedazzlement - roaring speeches, magnificent demonstrations, stylish symbolism, and unrelenting tugging on the heartstrings of national pride and national vengeance. That's why to this day neo-Nazism tends to appeal to the more blunt-minded among us - infantile skinheads attracted by shiny things.* The Third Reich should serve as a lesson, to always remember the supremacy of human Reason over mindless animal emotion.
*Although I would warn that appeals to emotion can take hold of even the smartest of us. The Nazi hierarchs were not unintelligent men.