The ADL, the left-wing Jewish human rights group not aligned with Musk in the slightest, called out that Musk's gesture was merely an awkward salutation, not a Nazi seig heil[0].
The left wing Jewish human rights group isn't the arbiter of what a nazi salute is. Actual Nazis around the world took it as a nod towards their ideology, and he's desperately trying to start a civil war in the UK, so I would say it walks like a duck and it quacks like a duck.
[0]: https://www.jta.org/2025/01/21/politics/how-did-the-adl-conc...