It may be his right to stay in his seat; but, if the owner says go, he should go - because the law can't provide a peaceful solution to all situations.
There was a standard of proper behavior for the airline, too—and they violated it:
‘Demetrio [one of Dao’s attorneys] declined to discuss what kind of damages Dao might seek in a lawsuit, saying he doesn’t know the extent of the physical, emotional or psychological damage the man suffered. But, he said, the airline did not have the right to use “unnecessary force and violence” to remove a passenger who is not a threat.
“Common carriers have the highest duty of care to provide protection and safety to its fare-paying passengers,” he said, adding that the Chicago airport police who dragged Dao from the plane share in responsibility for the incident.’
http://www.latimes.com/business/la-fi-live-stream-david-dao-presser-20170413-story.html