He was removed because he refused a request from a Flight Attendant. The word was incidental, but FAs have the authority to remove unruly passengers for any reason (though they do have to check with the Captain who has the final say).
See my reply #5.
I wish someone would test that in court.
Until then, I will be happy to continue to refuse set foot on an airplane.
Yes. An airplane is private property. The 1A simply does not apply there. If you think the airplane’s staff grossly overreacted, contact the company later. Or file a lawsuit.
But don’t argue with the staff. You really don’t have that right.