Posting a person's current location or private/personal information with the intent to expose or harm them is doxxing, and shouldn't be something Twitter tolerates, especially given its scale.
Showing a video of a guy who threatened your family several hours after the event and asking for help IDing that person through publicly viewable information like a license plate is not doxxing. Though if a mob starts tracking that info down and posting it publicly, it can lead to it.
Running a real time flight tracker showing the location of one person's jet all the time is skirting the line of doxxing pretty hard when we all know why the tracker was created. Let's not pretend that this is the same thing as just looking up normally accessibile info.
However...
Amplifying the existence of the database that tracks someone's location with intent to make it more widely known is worse than the existence of the database itself.
See also: Anyone could look up county records and find names and addresses of homeowners, and that's fine... But if you use those records maliciously, that's a problem.
Some of the "journalists" resharing the flight tracker were clearly just trying to piss off Musk, who had just said that it would be against the rules. The fact that they got banned is what they wanted, like someone who goes to a protest hoping to be photographed in handcuffs. They got what they wanted, and their complaints are hollow.
They're especially hollow because they spent years cheering abuses of authority on this same platform and are actively refusing to cover those abuses now that they've been thoroughly exposed (which is also why they're mad at Musk).
The news headlines I've read since, have only reinforced my antipathy towards the news media. They all talk about journalists "covering" or "criticizing" Musk. None are saying "who violated the rule Musk just announced".
The rule itself is too vague, probably too capricious, and needs clearer enforcement terms and enforcement mechanisms that are going to be equally applied. So those who were banned should be unbanned now, until the TOS are clarified.