There are a number of defences/justifications when it comes to recording situations like this:

- The person who used disproportionate force on the passenger may well have committed a criminal offence. This would justify recording.

- The event is undoubtably in the public interest. This would support releasing into the public domain.

If my flailing body were dragged down the aisle of a United aircraft until I was bloodied and bruised, I'd want every single news organisation in the world to re-play the footage as frequently, and for as long my as possible, until everyone knows what a nasty & despicable company United Airlines is.