That's motte and bailey on "harmful". Nobody is banning people for saying Musk is a moron, nobody is advocating for "There is a <slur> walking on so and so street right now" tweets. Criticizing people vs revealing their precise current location to everyone on Internet are very different things.
This is public information. His own plane reports it. Anyone can buy a receiver to pick up the transponder, and websites exist to collect that data from people who do. All this Twitter account does is report that for one plane in that database. Anyone, including stalkers, can make a script to watch it.
