It's not "inherently progressive". The rate is flat and therefore not progressive in the technical sense, though the result can appear that way. People tend to self-select into the highest tier housing they can afford. So, the tax can feel progressive even though structurally it isn't.
To see that it isn’t truly progressive, consider someone buying property with accumulated wealth. The tax only increases proportionally with the property’s value; the rate itself never rises.
This statement and the article title are disingenuous. Mamdani wants to avoid increasing property taxes and drawing down city reserves to balance the budget here.
New York City is legally required to balance its budget. This is the reality of that.