How do you know "a passenger threatened a flight attendant"? Are you merely going off of the allegations of the flight attendant (which btw is what the governement has built the case on)? What if the flight attendant is making the whole thing up?
Because the passenger admitted he did so.
He now says his threat was directed at the flight attendant's job, not the flight attendant or the aircraft - but his threat was quite vague.
In the future he will probably not make anymore veiled threats at aircraft personnel. But you never know, since he is demonstrably a lecherous idiot.