Benjamin Tisch’s shot at Mamdani during the Met Council gala comes just two weeks after his sister accepted Mamdani’s offer to remain at the helm of the NYPD.
“The two of us will not shy away from the fact that we hold disagreements on certain issues … but I also believe that these disagreements are not only reconcilable, but they are the sign of a healthy partnership to come,” the mayor-elect said in an interview with The News last month.
These are the kind of ghouls you want to work with if your plan is to sabotage yourself out of the gate. 
He has committed to keeping Tisch as commissioner, that’s not just a take.
As others have pointed out, if you’re going to piss off the police, at least get in power first. His commitment isn’t indefinite, either, and firing her after an inevitable police screw-up could better minimize reaction.