Let me explain something to you.
Autistic people are not children. They are also not sociopathic narcissists who lack empathy. Autistic people are sometimes hyper empathetic, to the point of being overwhelmed by other people's feelings, but due to differences in neurological development can be discriminated against for missing social cues or having nonreactive facial expressions.
However, conditions can be comorbid. Some autistic people are also narcissists, or sociopaths, or have mental illnesses, or are just assholes.
Do you know an easy way to tell the difference? Tell them how you interpreted something they did or said (or didn't do or say) as harmful or lacking in empathy. An empathetic autistic person will apologize, validate your feelings, and explain how they felt and what they really meant, even if it was hard for you to interpret.
Elon Musk has heard the backlash. His response was insufficient, stating that his detractors need "better dirty tricks" and that "everyone is Hitler" is "sooo tired".
That's not empathy. That's not an apology. That's not contrition. That's downplaying. That's lack of accountability. That's sane washing. That's misdirection. That's gaslighting. That's DARVO (Deny, Attack, Reverse Victim and Offender).
Note that he did not say it WASN'T a Roman or Nazi salute.
He meant it. He practiced it in advance. He did it twice just so there wouldn't be any confusion.