What am I missing?

This seems to me very simple and obvious. It is not among the goals of police work to shoot and kill unarmed citizens. If that happens, we can conclude that the police officer did not follow a proper protocol, and the officer's conduct was not what we expect of police officers. The proof of this is the dead person.

It is preposterous to say that the officer may be justified in his actions and that this may be a "good shoot," as they say. Res ipsa loquitur. You had a live, healthy, unarmed person presenting no danger to anyone. Now you have a dead person. That is bad. The police officer did it. The police officer did a bad thing. We can go ahead and learn more about the events but we already know enough to say the above. QED.

And, if I may go on, what Americans do not seem to understand is that the purpose of guns is to kill. Guns are machines designed and manufactured for the sole purpose of killing large metazoans, including humans. That is all they are good for. That is why they exist. That anybody would think that a child should be taught that it is fun to shoot guns is just sick. If you happen to be among the few people on earth who feed themselves by hunting wild animals, then it's your job, and maybe you need to teach your children how to do it assuming they will survive by the same means. Otherwise, the purpose of guns is to kill humans. That is not fun.

Automatic rifles are for the latter purpose -- killing humans -- only. If you think that you should provide your nine year old child with the fun experience of using a machine that exists for the sole purpose of slaughtering humans, you are depraved. And depravity is, of course, a God-given right embodied in the sacred Second Amendment to the Constitution, the only one that counts.