I think that weird semantic nature is because there's more than one entity involved here.
AirBnB is just a platform. It is, by itself, legal. However, virtually everyone who uses AirBnB uses it illegally.
Thus, it's not illegal (because AirBnB the service is not forbidden) but it's not legal (because it's hard to use the service without breaking the law, and in practice almost nobody does what's required).
AirBnB is just a platform. It is, by itself, legal. However, virtually everyone who uses AirBnB uses it illegally.
Thus, it's not illegal (because AirBnB the service is not forbidden) but it's not legal (because it's hard to use the service without breaking the law, and in practice almost nobody does what's required).