I have witnessed multiple people do this, and it never feels like it's done in good faith. They assert that "Only Elon Musk knows what his intentions are, and unless he explicitly states what his intentions were, you cannot speak for his intentions". They say that the accusation that he is a Nazi is slander for this reason.
I'm wondering what the name of this kind of tactic is. They'll say "You cannot speak for another person's intentions" while sometimes also saying "What was perceived did not match his intentions" and "The Romans also did that salute". In the process they will also state several times that they are not defending Nazis and that they hate Nazis.
It's called nazism. People who defend nazis are almost certainly nazis themselves. People who claim the nazi salute was used by Romans are wrong or lying, and also probably nazis; the earliest known record of the salute in a Roman context was created a millennium after the end of the Roman empire.
Edit: It's probably worth noting that Hitler was likely a fan of the Roman empire. Nazi Germany was known as the "third reich" where the first was the the Holy Roman Empire and the second was the German Empire. It's likely they appropriated the gesture thinking it was a legitimate Roman salute.