Is it just something they view as a disability and therefore weak or "defective"?
There is no deviancy, voluntary or otherwise, that reactionaries can abide. Given sufficient time and gunpowder, they'll wipe everyone else out first, and then when there's no more deviants outside the movement, they'll turn inward to find entirely new, finer grades and deviancy and wipe themselves out.
A lot of them are autistic as well, they just fell into reactionary thinking for whatever reason. I remember Destiny was talking to some incel/alt-right guy that had a speech impediment and was clearly autistic, yet this guy wanted to remove all the PoCs from America so that he would have a shot with white women lololol.
They hate us cuz they ain't us.
They just use any group that isn't part of the hegemonic, culturally dominant ingroup as a scapegoat for society's problems. They hate us for the same reason they hate trans people, all queer people, people of color, and any other marginalized group: if you already have a group that stands out in their difference from the ingroup, you can shift blame on them and they won't have systemic power to fight back.
Unfortunately, I've met a lot of autistic reactionaries (esp in the tech community)
I don't doubt it, just like you'll meet Black reactionaries or gay people who hate trans people, etc. Reactionary tendencies are very common when people come face to face with the status quo's contradictions without the necessary tools to identify capitalism and settler colonialism as the roots of the problems.
they're obsessed with strength and view homogeneity as the primary source of it
Which is funny given all the horror stories about communism taking away individuality.
It’s part of the reason. But the newer, online generation of fascists have also seem to realize that much of their base is also autistic, or they are themselves but are unable to recognize it. I imagine it causes a lot of dissonance and resentment because they’re supposed to be the ubermensch but they’re also “defective”. And the culture they’ve bred doesn’t tolerate it, so they receive almost no support from anyone
It’s like how many incels are also white supremacists while simultaneously believing that they’re individually inferior, either due to genetics or because the Jews brainwashed them into watching cuck porn or whatever. The culture they’ve bred encourages people to punching down on their own community and escalating into more antisocial behavior. They’re unable to process their two contradicting fundamental beliefs.
The path of least resistance for both groups is to commit mass murder or just being antisocial to the groups they hate.
People who can't understand social cues can often come off as abrasive or cold to other people. It often takes a fair amount of work from neurotypical people (not denying it doesn't take the same from autistic people) to fight emotional programming and not be bothered when autistic people do things neurotypical people wouldn't.
I think being both willing and able to conquer instincts and social programming is part of what makes someone less likely to be reactionary.
setting aside the treadmill of replacing a slur with autistic (derogatory), autistic people is a broad category both for this question and probably for the motivation of their hatreds.
they could be rounding up needing any amount of support with "useless eaters" but i think there's a separate revulsion for people acting weird. doubly so if the neurodivergence came with an unusual face shape.
the nonverbal kid tied to the front seat of the bus and loudly stimming at 7 am is annoying as fuck and presents a competing accessibility need for everyone else but you should be mad at the adults responsible for putting you all in that situation.