In some cases, you’re making a legal judgement about the interpretation of the contract. Just curious if you have legal background to support those interpretations. In particular, your point #7 — I am not a lawyer, but based on other instances of people being ordered off aircraft (including the really obnoxious “this foreign looking person next to me makes me nervous”), I’m guessing the Courts have granted wide latitude to the airlines to make a determination.
The other point that I’ve read elsewhere is the airline has not just a moral, but a legal obligation to do everything reasonably possible to fly a scheduled flight. Under those terms, the need to get a flight crew to another location to make that flight (and the associated thought that ‘keeping 50 people from getting to where they’re going is worse than keeping 4 people from getting to where they’re going) would seem to be a legitimate reason to bump a revenue passenger.
(And I’ve been in the situation where I got into an argument with ground crew when onboard the aircraft. I was told, “If you want to discuss this more, you need to leave.” I got up, gathered my stuff, exited the aircraft, booked a flight home on another airline, and then had an extensive discussion with the supervisor.)