The manager has made a request for a task that needs completing in a gentle, nuanced way, and expects a gentle, nuanced response back. Even "Ehh. That's not the kind of thing I really enjoy doing".
We can fault this employee for not knowing how to communicate, and that’s fair. But it’s a much bigger fault with the manager for not knowing how to deal with it. After all, of the two people involved in this exchange, one of them has “deal with other people” as their entire job description, while the other one has “deal with your manager” as one job requirement among many.
Is it so hard to ask “why not?” if a simple “no” isn’t enough?
But someone who does not understand the employee's autism might leave satisfied with why the employee would not like to complete the task, but assume that the initial blunt "no" was deliberate disrespect or disregard for the manager's request... and after a series of interactions like this, come to an erroneous conclusion that the employee desired to be uncooperative or doesn't care about showing any regard for our feelings.
Understanding why helps us be empathetic and "not take it personally."
I'm probably on the spectrum the way I read that is it's the managers feelings that are the root of the problem. The manager learns to manage his/her feelings and the problem is resolved.
(Obviously, this doesn’t apply to things like targeted harassment. I’m talking about normal work discussions with troublesome replies.)
Obviously, this is hard to actually do. But it’s good to try, and management should definitely do this, especially with their subordinates.
It could also later come back to bite you with the person claiming "But you said you wanted to do that", even though you were just doing it because they were asking.
This reminds me of some party of math students. One math student (clearly not on the spectrum!) X asked another math student Y: "Do you know whether Z will come?". Y answered: "Yes, he will come, but later.", to which X answered: "I didn't want to know whether Z will come, but only whether you have the knowledge whether he will come. If I wanted to know from you whether Z will come, I would have asked you 'Will Z also come?' and in the worst case gotten the answer from you that you don't know. But this is not the question that I asked. So, you should immediatelly have concluded that I am not interested whether Z will come, but only in whether you have the knowledge about that.".
I could tell lots of such stories about such ultra-precise questions and expecting precise answers among math students.
TLDR: Communication styles differ.
Just another reason never to assume the worst and always ask for clarification if you don’t understand.