IMHO: The article is too much rage-laden. The much more interesting article comes beneath the one linked ( https://www.wired.com/2017/04/united-airlines-overbook-fligh... ). At the core doesn't seem to be evilness of capitalist corporations, but rather a) the economic usefulness of overbooking b) an uncooperative (ex-)customer (his refusal to leave being unlawful) c) an unqualified and brutal airport police d) the di…
It is exactly what booking a seat is: buying an entitlement to seat in that plane for that specific flight. Otherwise what's the point? I understand that overbooking can be useful for companies, but in that case they should just buy back the service they oversold. That's how markets work.
Property rights are not everything. What is protected in a market economy is the free transaction between two economic actors. United's property rights of the plane, of course (even though it's likely to be leased, anyway), but also the rights created by the contract between the carrier and the passenger. If you don't protect these rights, you have nothing like a functioning market economy. Capitalism relies on social structures able to protect rights.