As someone who's flown frequently and worldwide for five decades, I was surprised to learn that I could be asked to deplane for non-safety reasons once I've boarded and strapped myself in. I've always accepted that I could be 'bumped' at the gate if, say, seats on the plane were unusable for some reason, but I'd assumed that once I'd put my luggage in the overhead locker and started reading the safety card, the airline had 'accepted' me. I've never encountered an on-board bumping, even flying internally in the USA (the one milieu where US airlines cannot be avoided, sadly). If I was asked to deplane for some kind of financial recompense, and declined the offer, I would expect that to be the end of the matter as far as I was concerned. If I was asked more aggressively to get off, I'd be alarmed, indignant and scared. If I was then confronted by three large men in jeans who spoke menacingly and laid hands on me, I'd be deeply confused on top of being alarmed, indignant and scared. I'd have no idea that the airline had legal small print in its favour, as I've never read the small print for any of the many airlines I've flown, like 99.999% of passengers. I wouldn't have a ticket to read -
like many people I'd be travelling with just a barcode/boarding card on my smartphone. I'm fairly sure I'd resist, purely on the basis that I was safer on a plane full of people than in a secluded part of the airport with these three large, threatening men whose link to official police seemed unconvincing. I'd be especially scared if I were elderly (actually, I am), small (yup, that too), and Asian (I'm not) in a country where Asian people had been attacked or murdered in 'safe' situations. So this man's reaction seems wholly understandable to me, and the idea that he should have smiled and gone along with the whole deal sounds like the view of someone inured to unquestioning obedience.
As someone who married into a family of aviation professionals, I'm not so surprised at the attitudes of some posters here. Aviation is a peculiar industry in that it can only provide a safe service if its employees adhere absolutely to rules and SOPs, and obey others without question. However, the industry exists for the sole purpose of servicing human beings who are NOT trained in that strict obedience. Moreover, airlines are hugely keen to sell themselves on the basis of providing a comfortable and effortless service - the last thing they want is pax feeling intimidated by quasi-military authoritarianism. I can see why those who must conform to strict rules and discipline resent those who don't - but the resentment is unfair and irrational. Airlines can't exist without passengers, and passengers are simply people paying money to get from one place to another, not volunteers enlisting in the marines.