No, it's broadcasting the movements of a set of
aircraft, using publicly available data. There is no information about who is on board those aircraft.
Nobody has any right to privacy regarding the flight movements of their aircraft, and indeed any idea in that light is antithetical to the entire principal of air traffic control and safe air travel. The idea that people would not be able to track his aircraft if this account is gone is ludicrous, as there are both other flight tracking websites, the ability in some areas to get full flight plans, and even if you're a stalker the ability to just listen into ATC radio near the routes his aircraft use.
You even have spotters who spend all their days at airports logging all aircraft and posting the results online, as they've done for decades, so there's no way for aircraft movements to remain secret for long.
By buying private jets and choosing to use them exclusively, Musk himself gave up his right to any privacy when flying on them. He has other options, such as flying commercially or chartering aircraft, as others in his position have done, but has chosen not to use them. He's now trying to change the rules for everyone else to carve out an exception for himself and other super wealthy individuals.
It's rank hypocrisy and bullying and I'm amazed so many people on HN are supporting him in this, and choosing to believe him rather than reading up on how open this data already is.