I would encourage you to watch the whole video of the incident, with sound, and then put your hand on your heart and honestly say you think that was a sieg heil. (but don't throw it to the crowd after)
This is even more true for the latest copycats from CPAC, which show that the Fascist salute is being normalised and becoming a MAGA symbol. Think about that. Whatever Elon's original intent, the American right is now knowingly doing the fascist salute, not as satire but as a open sign of their politics and provocation to their opponents.
https://en.wikipedia.org/wiki/Fourteen_Words
https://theconversation.com/musks-inauguration-salute-is-not...
I also don't know why HN keeps these Elon posts up because they're always a shit-show of reddit-ness and I believe most other similarly high-conflict subjects would have been nixed by now.