I think this argument that United Airlines was within its rights is well-articulated.
I also think the author misses that there are sometimes a big difference between what is contractually legal and social norms. A reason the United Airlines case is receiving so much attention, most of it against United, is that it grossly violates social norms whether or not it violates the law.
The speed limit is 65 mph (what is legal). People often drive 70 mph (social norm) without fear of being pulled over. Do people receive tickets for doing 70 mph? Yes. Does that stop us from breaking that law? No. Have we all driven past a police officer while going 5 mph over the speed limit without getting pulled over? Yes. Lots of times.
In the United Airlines case, social norms are saying that paying for a ticket should not carry the risk of being forcibly removed from the flight.
Social norms are also saying that airlines, not its customers, should pay a fair price if the airline decides it needs to remove passengers.
Maybe articles like the one I linked to will help change social norms.
I hope not. I’d rather that the pressure from social norms cause airlines to rethink their overbooking policies to come up with something more agreeable with social norms than converting paying customers into trespassers at the airline’s whim.