AirBnB allows housing stock that would otherwise be inhabited by long-term residents to be reappropriated for tourism and business travelers. That puts local residents in direct competition with tourists/businesspeople for housing, and predictably increases the price of housing for long-term residents.
By regulating the hotel industry and restricting the supply of short-term housing, local governments favor long-term residents over visitors. AirBnB is great for travelers, but long-term residents pay the price.
> it just indicates there is existing unsatisfied demand for short term rentals
Yes, but allowing the market to satisfy that demand is not necessarily a good idea. This isn't a case where the unrestrained market will solve all problems. It will solve a problem for travelers, but create problems for long-term residents.