I wonder if you know what duty means in this case.
Posted By: ironman1315
Date: Monday 10 June 2019, at 10:36 pm Recommended by
It means a legal duty. In that an individual is protected from civil liability (barring some statutory scheme to the contrary) because they don't have a "legal" duty to protect. This, in many respects, is very narrow in its reach. The officers involved could still be reprimanded, disciplined, fired, etc. The department could be audited and crushed by the state. There are a host of options. Civil liability is not one of them.
(note that this doctrine is far far older than your cited case.)
What it is not, is an agreement that something could have been done better. It is a recognition that imposing a legal duty is bad policy. The police could have and should have done better. They didn't and now a woman is dead because of it.