There was no security issue, there was no emergency, there was no legitimate reason to remove this person from the plane. The abuse and physical harm of a passenger was done entirely in the name of saving a few dollars by not sending their staff on another flight.
This was wrong and it was an abuse of the security personal to enforce their monetary needs.
Separately, the security personal should be fired -- for also being utterly unprofessional, unable to read the scenario, and reacting with unnecessary force.