Many autistic people will often make gestures in an exaggerated, jerky way.
It's as if -- despite your intentions -- you forget to make the gesture as you're naturally inhibited, then you actively make a point of doing it quickly, appearing awkward, forced and over the top. Often seizing up and repeating things too.
A great example is shaking hands. In the space of a few seconds you can go from intending to shake someone's hands to feeling a sense of social inhibition that stilts you, then you rapidly over-compensate while also trying to deal with the dynamics of the social situation, at which point you fling your hand up rapidly and literally miss the handshake or even hit the other persons hand.
Here, Elon is gesturing handing his heart out but overcompensating with a more rapid, intentional movement. A normal person would just decide to make the gesture and do it in a relaxed way because it's muscle memory and their mental bandwidth isn't being eaten up by completely different trains of thought.
It's the rapidity and intent that makes it look similar to a Nazi salute. You take that way and it's the "from the bottom of my heart.." gesture.
Even before all this, just assuming and asserting the worst is idiotic. It wouldn't even make sense.