On the contrary he was within moral rights to insist on staying. Legality is another matter. Overbooking should be illegal, certainly in it's present form. Once one has sold a ticket for a seat then it is sold, it ought not be possible to sell the seat twice. That is fraudulent. (Possibly non-show last minute bargains being an exception.) Refusing to move should not be considered disruptive, it should be the norm: demanding a fare paying passenger who has done nothing wrong, will move, should be considered disruptive and illegal. Assaulting them to force them off should result in immediate loss of the job of the individual committing the assault, and probably legal proceedings. But the law seems biased towards commercial companies, who in this case appear to be at liberty to do just what they want, and make the victim the one who has broken bad law.