After overbooking a flight, United Airlines realized they needed room for a crew that would be working another flight. They looked for volunteers to leave the overbooked flight, and even offered incentives but no one was willing to change flights. That's when they randomly selected this man, and others, to deplane but he refused. The used excessive force to remove him from the plane. It looks like he was even knocked unconscious.
Warning: this is somewhat disturbing to watch. I can't believe anyone with the airline thought this was a reasonable solution.