That's why I say he made the case inadvertantly.
He derided Darwin, yet his own theories such as that of "The Superman" led toward a type of social Darwinism.
'Social Darwinism' is a 20th century term that had nothing to do with Nietzsche. And even a phrase like 'Survival of the fittest' was coined by British Sociologist Herbert Spencer. Nietzsche didn't agree with Darin or Spencer and felt that weakness (societal or biological) was a needed step of moving forward. his concept of the Uber mensch was in terms of achievement, not brute strength as the Nazis fraudulently put forth based mostly on his sister's forgery. Nietzsche would have despised the likes of Hitler.