Probably the same rules the NY Post broke when they got banned, "don't post things on Twitter that make the people in charge upset".
A link to an article was banned. Also, no one at the New York Post was willing to put their name on it, there was no byline at all. Considering the sketchiness of the source at the time - no byline, a stolen laptop, etc - wasn't really a hard call to punt on it.
Clearly the expectation of privacy for corporate jets, frontrunners in the emerging battle for control over our data.
Anyone can get flight information. The FAA makes real-time flight information available (ADS-B). Individuals can request to keep their info out of the public feed. So no expectation of privacy.
Someone with Musk's public stature and apparent addiction to publicity will struggle to argue for any expectation of privacy.
I think the person who you are replying to was being sarcastic. These journalists have not been posting flight data.
Elon is claiming these journalists were doxxing him which resulted in his family being attacked.
Make of that what you will.
The only rule most of them broke is "don't upset Elon Musk".