Here is an essay in response to Weikart by Robert J. Richards, Professor of the History of Science and Medicine at the University of Chicago.
For my part, the reasons for the rise on Nazi Germany are diverse, complicated, layered, and often contradictory. Histories of that period are complicated by the fact that you cannot say Hitler crossed the street without touching some nerve and inviting blowback, so any degree of nuance tends to be lost to some caricaturized narrative. The Nazi’s were certainly fixated on race and believed in a hierarchy of race, running around with their calipers measuring skulls and such. For the most part, I expect they just started with their conception of Aryan as the master race and grabbed slogans to support that wherever available. It was of no consequence that evolution is not teleological. What mattered is that people had the notion that survival of the fittest was progressive, and that Germany’s rightful place was at the apex.
The regular Nazi torch bearer may not have been very particular about the details. My sense is that what really propelled the rise of Hitler had more to do with post great war economic collapse and reaction to policies in Bolshevik Russia involving state seizure of industrial and agricultural assets, and resulting in mass starvation in Ukraine. This presented a very real existential threat to ordinary Germans, and tilted the body politic to the worst demons of nature.