FAR 91.3 and 91.11 exist for operational safety of the flight. The purpose of the FAR is the PIC can ignore company, customer, and even Air Traffic Control orders that compromise the safety of the flight. Company says you must land at this airport tonight, and the pilot says well it's socked in, it's not safe to land, so no. That's the purpose. It's to make him accountable to flight safety, not the company or anybody else.

By making him an agent of his company's customer service to remove a passenger who is in compliance with the law, regulations, and the company's own contract of carriage, and then use FAR 91.3(a) as an excuse to say the pilot must be obeyed is poor logic. And I am a pilot (and a former CFII). I think it makes flights less safe to inject the company's demands into the cockpit. They do not matter, what matters is safety. That's what his FAR is about, not to enable the pilot to be an ass to passengers on behalf of his moronic company.

And claiming otherwise damages the necessary trust that we're supposed to have, and should have, with pilots and crew. Their primary purpose is to save your life. It is not to pour sodas, or appease the company CEOs profit needs by being jerks to passengers, and throwing them off for business reasons.

As for the police, I think that was an illegal assault on the part of the officer, and given the available information the passenger wasn't breaking any laws, so the police being there was inappropriate in the first place, they shouldn't have intervened and should know that.

Edited a few times to remove foul language :-D