Then you would violate your financing agreement as the rent would be below the capitalization threshold and you would have to cough up money to the bank.
I don't think you understand the issue.
The issue here is that many of these financing agreements specify a minimum rent and if you fall below that you are in violation of the capitalization requirements and you owe the bank money. By contrast, missing rent is considered a temporary condition and can be tacked onto the back end of the financing agreement.
So, zero rent does not cause capitialization issues, but lower rent does. Thus, landlords have a perverse incentive to leave a place unrented rather than lower the rent.
An occupacy tax breaks that perverse incentive.
The goal isn't to grind up landlords. The goal is to cause rents to come down when they should. Right now, the back end financing agreements are keeping rents artificially inflated.