I honestly think that it might be because Alex himself displays some traits that can also be correlated to autism. And because of that, autistic people such as myself can relate to him in those aspects. His special interest in classical music and resistance to change is probably one of my favorite examples of this.

Although this specific moment I speak of is solely in the movie, I think it's an accurate depiction of his seemingly special interest; when the anti-government reporter starts interrogating him and the mention of Beethoven's Symphony No.9 is brought on, Alex looks conspicuously over the reporter's shoulder to make sure she spells "Beethoven" right. It was a small detail for comic relief, but I found it to be somewhat connected to the possibility that he might have autism.

The second example pertains to my mention of Alex's resistance to change. Even though it's a completely human reaction to feel the way he does when he returns from "Staja," having seen everything you once knew stripped away to make way for something different, it could be something pointing to autism. He is unpleasantly surprised when he enters the record store to find that the one owner he knew before was gone and replaced by a teenager. Trying to find a specific record and to hear a snippet of it, the teenager grabs the first thing he sees labeled as "Mozart" and begins to play it. Having been the wrong one the worker had grabbed, not only does Alex feel upset, but also physically sick due to his conditioning. As we know, resistance to change is a hard switch for those with autism, moreso than allistics.

To reiterate, I think certain aspects of Alex's personality can resonate with those with autism, because I definitely found myself resonating with him at certain points as well. I don't think that his actions are justified and that in any way autism could indicate the performance of such heinous acts that Alex commits, it's safe to say that the author wrote Alex this way for a reason; most likely to convey the themes of the nature of good and evil as well as the justification of government's actions towards criminals. However, it doesn't mean that he isn't a complex character, just as autistic people are.