Delta have done nothing wrong in this case, say the plane took off and he started doing shit like that and a passenger got spooked (rightly or wrongly) and decided to try and stop him by force, it then becomes a much bigger danger and more of an issue.
There is no over reaction when it comes...
It turns out he has a history of trying to cause trouble on planes and then playing the victim when one back fired and he was kicked off, more than likely getting the reaction he wanted.
He should be black listed from all future flights and potentially prosecuted.