This account wasn't even 'putting those pieces of information together', he was tweeting it directly from ADSB Exchange, one of a number of collators of ADS-B Out data.
Aircraft movements are not private and haven't been for decades. If you want privacy in your air travel, don't fly everywhere on 1-3 well known private jets.
That said it's just as legal for Musk to kick anybody he wants out of his new club house and even be a hypocrite about it.
I just wish he'd get back to saving the world and setting up Mars for my kids. As a social media icon he's basically worthless to the world.
That was never going to happen. It's just a way to get people to work their asses off to further his real goal, to amass as much wealth as possible. Ironically, buying Twitter may well end up undoing that.
That doesn’t mean somebody putting those pieces of information together and regularly tweeting your movements isn’t creating a security risk for you. The choice that you make to buy a car or drive it in public also doesn’t mean that you have to welcome automated stalking.