Most of that quote is talking about how the mental institution is representative of the routine nature (or un-nature) of modernized society and civilization. The enforcement and oppression of forcing humans to conform and become gears in a greater machine, removing their humanity and basic animalism (represented by their libido). Additional bleakness is layered on when a force of nearly unstoppable humanity, impulsiveness, and individuality is crushed by the enforcer of modern society for stepping out of line.
In that sense, it's entirely possible that by comparing Nurse Ratchet (who is an allegory for the enforcement of modern social routines) to Hitler, you would be inevitably comparing all of modern society to the Nazi regime, which seems a bit harsh. I mean, in the first post you compared Hitler wanting to exterminate mentally ill people to Nurse Ratchet refusing to let them watch baseball. Again, when going off of the vague and general ideas of characters being oppressors or being parts of larger scale schemes (which would flow naturally from being an oppressor in the first place) it is possible to compare anybody to anybody, thereby unintentionally legitimizing much of the crazy speak that stathmk had mentioned in his post (about comparing every United States president ((or in some cases, the Pope)) to Hitler or Mussolini, or comparing any major world power to the Nazis).
Anyway, many of the comparisons derailed from your original starting topic of criminal insanity.
One of my favorite philosophical dilemmas was that of free will and determinism. There's a bit of a false dichotomy that people fall into- either everything in your mind is guided by what is in nature and how your brain processes that, or you have free will. How would you know? Many people seem insulted by the idea of their brain simply responding to outside stimuli and computing results based on this, but what is the alternative? How is that not free will if it is your brain the calculates the outcome? Is it free will if your brain comes up with something completely outside of the parameters of what is known to you, fed to you from the outside world?
Of course not. If your idea of free will is your brain coming up with conclusions and ideas that have absolutely nothing to do with anything then your brain is just a random generator and your mind would be useless- you would be insane. With that kind of "free will" you could honestly believe from one moment that two plus two equals fish to the next moment believing that two plus two equals Santa Claus.
Why do I bring all of this up? Because when it comes down to it, we are all presented with the same reality, but our brains calculate the data in different ways and come to different conclusions based both on how our brains are set up to begin with and what information we've taken in to be true as we develop our problem solving skills. You mention people who are criminally insane but 100% in control of their actions- how would you even quantify or qualify that? You could hand-wave it as simply being evil, but that has only become more and more difficult to do over the years as psychological studies have advanced and we've been able to identify the disorders and mental oddities that cause the "evil" in contemporary malefactors.
People are people and no person is another person. Over-generalization and attempting to lump groups of people together almost always ends horribly. Goeth was a horrible person who did horrible things, but I would not him together with Hitler who was a horrible person who did horrible things, who I would not lump together with Stalin who was a horrible person who did horrible things. They were all horrible people who did horrible things, and some used similar methods or targeted similar people, but they all had different ideologies, different personal vices, different personality types, different ambitions, personal values, and likely different mental illnesses (and in Hitler's case, substance abuse problems). None of this is meant to create excuses for horrible people, only to show that the world is more complicated than mustachioed villains who want to leave the damsel tied up to the railroad tracks because they are evil.