"Rent seeking (or rent-seeking) is an economic concept that occurs when an entity seeks to gain added wealth without any reciprocal contribution of productivity."

What contribution to productivity do corporations or people who have enough spare cash to buy available land provide to a society?

AirBnB can be just a marketplace, that doesn't mean it isn't damaging to society at large. Excluding the moral aspects of that is an ideology based on capitalism, it doesn't mean it's right.