It's extra work for the management company / Board, but one of the primary drivers is that all the people in the building don't want a constant stream of people moving in/out. Expanding it to minimum 12-month leases means less disruption to people living in the building.

There is always a gap between someone moving out and the next person moving in; you need time to clean out the older renter and set up for the new. You have to do new paperwork, background check, etc. Every person you rent to has a chance of being a deadbeat; increasing your number of renters per year by 4x increases the deadbeat chance by the same amount.

You basically are multiplying the overhead by 4x.

Short-term renters do NOT treat the property the same as long-term renters, and renters in general treat property much worse than owners. It lowers the quality of life in the building when residents aren't on the same page.

I don't mean that I support NYC's blanket regulation, but any condo owner would have known the situation before they bought the unit. If they desired a income property they could have purchased elsewhere.