She didn't have an episode/fit/outlash (not sure what the right term to use is) so of course no one was bothered by her sitting there. But when she stands up and digs her nails into the person in the row in front's face?
What if she had the e/f/o 5 min later? How much time was left on the flight? Would a screaming (near) adult who is being forcibly restrained by her parents for 2-3 hours something the plane needs to go through?