Why? Because apparently they need some more incentive to keep units occupied. Also, even though a property might be vacant, there’s still imputed rental income there. Its owner is just receiving it in the form of enjoying the unit for himself instead of receiving an actual rent check from a tenant. That imputed rent ought to be taxed like any other income.
@CrimeDad the low homelessness is due to the highest rate of public housing outside of self-identified socialist countries. The first several decades public housing was primarily for relocated squatters and shanty inhabitants, but since the 1980s they’ve promoted it for middle class and upper middle class improving the public housing stock.