Schordinger's Cat writes:

The Origin Of Species is a scientific observation of the world, not a philosophical, political, or religious rambling. If Christians or anyone else are too stupid to see that.....then I doubt whether their one brain cell will cope with a more detailed argument.

You are overlooking that scientific statements about mankind can have clear implications for philosophy, politics and religion. Let's take an example: the scientific statements about the degree to which human DNA varies between people (ie. very little) has clear implications for racist ideologies. Similarly, the scientific account of the origin of man does have quite clear philosophical, political and religious implications. The Christians are quite correct to recognise that, and you are incorrect to ignore it.

Simply arguing that Hitler was a creationist doesn't really dispel the original slur on Darwin.

Actually it does. Showing that Hitler was a creationist who rejected Darwinism dispels the slur that Darwinist ideology inspired the holocaust. Why are you so reluctant to accept that, given that Hitler's creationist views are so clear in Mein Kampf and elsewhere?