On a deeper level, it’s important to remember the foucauldian perspective on mental illnesses, sexuality, various kinds of “deviation” from constructed social norms, and power, that the 18th and 19th century European attempt to categorize and organize the world went hand in hand with attempts at controlling it for the benefit of the few and the detriment of the many.
Description, Foucault would argue, was meant to control people, via internalization of the differences/ supposed deviations from the norm (be they mental, sexual, gender, etc) and external policing via the state, including both punitive (police/legal/new kinds of jails, etc) and “health” initiatives (especially with regards to assigning deviant labels to certain behaviors or mindsets).
The nazis were but one one consensus-shattering outcome of this expression of biopower. But we saw similar things in other western states and in the colonized world - sexual practices were defined and then criminalized, as were crossing of gender or racial norms (defined for the benefit of primarily white men in power). People with what were considered mental illnesses were put away in sanatoriums, meant to “sanitize” the public of their presence - often, especially women who were not white or were working class, sterilization went along with that. Various programs of segregation in the US were supported by the ruling class and many progressives, as good for the people being segregated away from “normal” society. The nazis pulled from many American programs (and of course eugenics was developed in the UK and US) to build their own dream society that would eliminate difference and deviation of all kinds, and hammer out perfect aryan individuals. They did it by one of the most wide-spread acts of human violence in the modern era, wiping out millions of human beings for no other reason than control and trying to perfect something that did not ever actually exist (an aryan “race”). The reality of that is so mind-numbing that it’s hard to wrap one’s mind around it, honestly.
But… BOTH SIDES for sure! 
