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.
Eh. You might’ve come off as educated-yet-a-little-overzealous at first, but now you’re clearly just a whiner with an Econ 101 textbook on loan and a his rusty lunchbox to rattle at the sky.
Keep on truckin’, kid. You’ll figure it out someday.