Well, I don't necessarily want to defend it, but I think there is a rationale to do with infrastructure. In the extreme case where everyone in a Hawaiian town offered a room to airbnb, the infrastructure would buckle under the increased population - not enough parking, some places are on cesspools that have limited capacity, water usage is a problem in some areas etc etc.

Granted there are also financial interests at stake, for example the state collecting a hefty room tax when people end up in hotels. But then that money goes to infrastructure among other things, so there is some method in the madness.