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.
No seconds until everyone has a plate. We all learned it as kids. Now let's do that with housing.
Fuck their capital. They don't deserve it. Take the empty houses and give them outright to those that need them. There are more empty homes in the US than unhoused people.
Those empty houses are largely in places where people do not want to live. If you look at markets where people actually live, it's a pretty different picture. A shack in the middle of the field in Nebraska does not help a homeless man in Manhattan (and he almost certainly wouldn't take it if you offered it for free).