Which is ironic because the guy was crazy. He was randomly selected to be bumped and the cops had to be called in to haul him off the plane, after pleading with him for half hour. What a self-important jackass - sucks he got a bad break with the lottery but if he doesn't go somebody else will have to take his place. That's not fair either.
No, it's not fair, but it wouldn't be fair to remove another passenger because this one felt he was too important to be bumped.
>United could have just increased the compensation until somebody left willingly.
Sure, and United paid for that mistake and then some. But just because they made a mistake doesn't mean the other guy did not act like a psycho.
>they chose to involve law enforcement, with predictable results.
Those aren't predictable results. Predictable results are: "United involved law enforcement, and the passenger left the airplane promptly". A more typical scenario would see him leave way before United called the cops.
The results may not be what usually happens but they are entirely predictable. Any time you get law enforcement involved, there's a decent chance that violence will ensue. The entire point of law enforcement is to be the sole state-approved user of violence.