I don't act like anything. I behave in a neutral manner. When a passenger becomes unruly, however, and refuses to cooperate, interferes with flight crewmembers in their duty, and poses a threat to the safety of the flight, then they're off the airplane. Period.
The pilot in command is charged with the safe outcome of the flight. As a pilot, it is my only concern. I do my utmost to make sure everyone is comfortable in every means, but my overriding concern, and my chief duty, is safety of flight.
I'm not concerned about the passenger who brags, or who is cheating on his wife, or who wears inappropriate colors, or who hasn't bathed or has screaming children. A passenger who poses a safety of flight issue, as clearly this one did, is removed. It's not negotiable, it doesn't need an explanation. There's no room for debate. It's beyond contest or question. Behave, or leave. Period.
Once a passenger has struck a crewmember, there can be no question at all that is or her options have run out. In the US, it's a federal offense, and taken very, very seriously.
A passenger who fails to comply with safety instructions is in the same boat. He or she will be asked nicely. Then told. Then ordered. A passenger who fails to comply (they're not safety suggestions, by the way) is subject to handling as may be required...and certainly not as the passenger may wish.
If the airplane is pushing back and you refuse to sit down turn off your cell phone, you'll be asked nicely. If you still refuse ("you can't tell me what to do" is belligerant) you'll be told, and failing that, you'll be offered the chance to leave the airplane under your own power before you're arrested and forcibly removed...but you won't be continuing on that flight. That's a pilot's discretion as well as company policy.
If you think that's hard for the passenger, I once had a First Officer who acted beligerantly in the cockpit, refusing to do something...only on the basis of "I don't want to." I dealt with it in my own way and continued the flight. In discussing it with the chief pilot at a later date, the chief pilot's immediate response was "I would have turned the airplane back to the gate and put him off." That's right. He wouldn't put up with it from a passenger, nor from a crewmember...even a pilot. How much wiggle room do you think that leaves for you?