My understanding is that two of the three who left the plane were indeed a couple.
As to the assertion that no one on the plane was traumatized by the event, how did you miss the reactions by all of the other passengers on the many videos! They were horrified! How would you like to take off flying on an airline after seeing said airline beat a passenger unconscious just to free up his seat so one of their employees could use it? Of course, reasonable people would have just gotten off, but the ends cannot justify the means.
What is lost here is that both the airline staff and the police both lacked the necessary skills in dealing with the situation properly. All that mattered was to get their way at any cost because they had the force of law to get away with it. This is why your rights (or lack thereof) are so important.