Consider the following situation: you have rented an apartment. You have signed a lease. You have paid your first month's rent. You have moved in. You are putting your artwork up on the wall when there is a knock at the door.
It is Jim from the management company. He explains to you that there has been a mixup, and they actually need your apartment to house some company employees who have just been hired and need temporary housing until they can find places of their own. He's terribly sorry, but you will have to vacate immediately. They will find you a new apartment as soon as possible, but for now you are out of luck. They tried to find someone to volunteer their apartment, but no one stepped up. So you have been randomly chosen. Get out. Now.
Naturally, you refuse. You have a signed lease. No, no, Jim explains to you, the terms of the lease allow the management company to reclaim your apartment in situations like this. You are quite certain he's wrong about this, and it just so happens you are correct, but you are not a lawyer and the lease is long and full of legalese and sorting out whether you would prevail on the merits would take quite a bit of time. In any case, you say to Jim, "Sorry, but this is my apartment. I'm not going anywhere."
Jim replies, "No, this is not your apartment. You're just a renter. You don't own the place, the management company owns the place. And the owner says: get out. If you don't, I will call security to have you removed."
You still refuse to go, so Jim calls security. Three burly guys from ACME rent-a-cop sporting badges and dark blue jackets with "POLICE" stenciled on the back show up at your door and say, "You are unlawfully trespassing on private property. If you don't leave voluntarily you will leave us with no choice but to force you to go." Again, you refuse, at which point they knock you senseless and drag you down the hallway.
This situation is exactly analogous to what happened to David Dao. The only difference is that instead of an apartment, Dao was occupying an airplane seat, and instead of a lease he had a ticket. Otherwise there is absolutely no difference.
I can think of a couple of possible objections, though it takes quite a stretch of the imagination.
1. Such a thing would never happen to someone in their homeSuch a thing has happened. It happened to my grandparents, except that instead of Jim from the management company it was Wolfgang from the Gestapo. (OK, I don't know if his name was Wolfgang. But whoever it was, he (and it was a he) really was from the Gestapo. The actual Gestapo, not some metaphorical Gestapo-like organization.)
In fact, a very similar situation actually happened to me. It wasn't exactly the same because it was a condo, not an apartment, and we had not closed on it yet. (In fact, to this day I have never been inside the place.) But the bank that bought the development decided to appropriate all of the units under contract so they could turn the entire building into a hotel. Worse, they decided not to return the down payments, instead offering to settle at 70 cents on the dollar. It would have been a slam-dunk civil suit except for two things: the purchase contract had an arbitration clause, and the civil jurisdiction in question turns out to be thoroughly corrupt. Unfortunately I can't be any more specific about the situation because the settlement agreement included a non-disparagement clause, so if I say anything more they could sue me, and they would probably win. But if you really want to know, I did write up the situation in detail before I signed the agreement. The internet probably has a copy somewhere (ahem).
2. Airplanes are different from apartments
Really? How? Because they have pilots who can order you off the plane? Apartments also have civil authorities who can order you to vacate under some circumstances (e.g. there's a fire, or the building has been declared unsafe after an earthquake).
Yes, airplane seats are smaller and more uncomfortable than most apartments (except maybe in Manhattan) and the term of the "lease" is shorter. But I don't see what difference any of that could possibly make.
I'd really like to round out this list with a third example, but I am wracking my brain and I honestly can't think of any other possible objections.