You might want to read something by his contemporaries on autism, those who were not Nazis so that association can't be immediately used against them. Also read how people diagnosed autistic were treated in, for example, USA.
didn’t you know he undertook the arduous and benevolent task of creating a special category just for those of you that were exploitable for your labour?
Compared to sending all of a bunch to a gas chamber sending only part is morally preferable. Obviously. Mentally impaired people were by default intended for extermination in Nazi Germany. The "Asperger's syndrome" diagnosis allowed some of autistic people to be considered curious, borderline genius, pathway to making a new supersoldier/superscientist or anything like that not involving euthanasia.
If at any point you find yourself coming up with reasons to defend a Nazi,
I don't care for emotional arguments containing no logical structure. Trying to feed that to your counterparts instead of something meaningful is the most morally repugnant position on any subject. The more morally loaded the subject is, the more repugnant it is to try this.
Do you have any idea how profoundly his work has negatively impacted every autistic person since?
His work should be considered in the context of others' work of the same time.
The notions that we lack empathy,
There are three things called empathy, of which autistic people have problems with one, and psychopaths with another. This is correct.
have some kind of extreme “male intellect”
Maybe you'd like it back in your cell, your highness? Oops, it's not exactly a cell, it's a gas chamber.
and/or psychopathy
It's not a weird concept, it's the obsolete use of the term. In the 40s psychopathy meant basically every disorder with intelligence not necessarily lower than average.
He was one of the first to try to identify and categorize us, not out of altruism, but because he saw us as a diseased branch of humanity that was situationally useful but ultimately unworthy of life. If that’s not worthy of demonization then I don’t know what is.
As I said, sending all of the bunch to the gas chamber instead of some.