> So if hotels produce the same kind of externalities, why are the regulators only focusing on Airbnb?
They aren't. Regulators are focussed on the externalities associated with short-term tenancy operations in general, which is why they have imposed regulations imposing safety and other constraints on such operations to mitigate the externalities, as well as imposing taxes to internalize the unmitigated externalities by shifting the costs on to the operations benefiting from the activity that produces the externalities.
What you perceive as focus on Airbnb is just the general focus on short-term tenancies being made manifest in a particular way because of a high-visibility group of people flaunting the rules that result from the more general focus on short-term tenancies.
They aren't. Regulators are focussed on the externalities associated with short-term tenancy operations in general, which is why they have imposed regulations imposing safety and other constraints on such operations to mitigate the externalities, as well as imposing taxes to internalize the unmitigated externalities by shifting the costs on to the operations benefiting from the activity that produces the externalities.
What you perceive as focus on Airbnb is just the general focus on short-term tenancies being made manifest in a particular way because of a high-visibility group of people flaunting the rules that result from the more general focus on short-term tenancies.