A vacant property (really, any ownership of property, period) results in an opportunity cost externalized onto all other members of society. That opportunity cost is equal to the land's value. In the middle of nowhere, therefore, that opportunity cost might be low to the point of nonexistence, but in the middle of a city downtown, that opportunity cost can be and often is on the scale of tens/hundreds of thousands of dollars (or more!) per year. That is wealth that is long overdue to be repaid back to the rest of society.
Why should a property owner who does not impose any of those costs (or imposes a tiny fraction of them) pay equally for them?
The apartment almost certainly already pays for all of these things.
> It has a massive carbon footprint.
Which can be offset or even reduced/eliminated outright.
We can't make that determination without knowing how much profit a rented bungalow can receive versus the apartment building. A bungalow in midtown Manhattan might very well house one of the world's richest families.
Fundamentally, LVT is a wealth tax. If you hold a large amount of wealth (land) but have no income then the tax would seem regressive from an income-based perspective. But from a wealth-based perspective, its a perfectly reasonable thing to expect those that own to pay taxes not just those who labor.