There are countless memes online showing pictures of other famous people like Alexandria Ocasio-Cortwz doing similar things.
Anyway, even if it was a nazi salute, what would that even imply about him other than the childish edgelord aspect which is already well publicized? That he wants to gas the jews?
What would it imply about him? He’s now a quasi-governmental figure aligning himself to the far right. He’s messaging to others on the far right that the federal government will tolerate them. Doing so will embolden them to take action.
Well that's definitely more plausible than the antisemitism...
That said? Musk is exceptionally bad at understanding how his words and actions will be perceived and seems to make no effort to send correct signals. While also being a frequent troll who likes raising his middle finger to the "woke".
It being a big "fuck you" seems far more in keeping with his character than it being a subtle Machiavellian communication.