Mago
Austrian Blech Machine
Police dogs are a confusing matter because they are trained more than your average dog, yet they seem to have a higher rate of attacks. There is a simple reason for this though. While dogs have been genetically designed through thousands of years of selective breeding, they still aren't very smart. You cannot train a dog that a certain group of humans are ok to attack but other humans are not. Yes the German Shepard Police dogs are trained to kill and they are let to believe that attacking someone is ok. Regardless of their training the whole concept is confusing to them and when that moment happens where they can't see that thin line, an accidental attack will then pursue. I say accidental because it was unattended due to the dogs confusion, if anything about a person reminds them of the type of person they would attack in the line of duty, they will attack.
This is why when you are around a K-9 unit the officer will tell you to stay away from the rear doors because someone can provoke the dog in the car, which makes a dangerous situation for the cop when he has to handle the dog. That is how much confidence they have in these dogs even when they are in the car. A dog cannot be trained to only attack certain people and not others, when you train a dog to attack, everyone can and will become a target, including the cop.
although you may have made a point about the thing that it can be confusing and so on, but tbh the rest of your post makes me go
Dunno how they do that at your place, but I'm quite sure that the training and way of using dogs in military and police services works different over here...or at least I hope so.