It is terrible to use a dog in such a manner. You basically have to brainwash the dog into treating strangers as enemies. Police dogs can’t be easily retired from their jobs, if policemen they’ve worked with don’t bring them home and assume the responsibility of a dog whose socialization with all other living things had been destroyed then they will likely spend the rest of their life miserably in a cage. One time dropping my dog off at the daycare/groomers/trainers a policeman brought out his K9 partner. This dog clearly wanted contact with every person and dog he saw but his partner had to drag him outside and into a car. Coming back in to pay the bill he explained how the dog was not allowed contact outside the K9 program save for the officer’s own family. He was being trained to consider all other as a threat, only reserving himself while under officer control. These are probably good dogs, almost all are, so I’m sure he obeyed his partner and was not a random threat to society, but there’s no accounting for all circumstances and this dog will never get to run free in a dog park with other dogs or ever be off leash around other people.
Don’t know why they’re considering a ban, but those are reasons enough for me. I wouldn’t treat a human that way so I’m certainly not going to treat a superior species in that manner.