The problem with these videos is that unless they run with full audio from well before the incident until well after, it is always easy to play expert afterwards. I doubt that the cops walked up, dragged her out of seat and off the aircraft. That just seems unlikely, especially for a large international airport with its own police department which presumably trains for incidents such as this.
Bottom line, the instruction is to remove the passenger. If she will not come voluntarily, this may well have been the least damaging way to do it. Bear in mind that law enforcement has an obligation not only to the individual passenger but to all others onboard and to themselves.