I will just say this - rarely does one "win" an argument or fight with a cop. You should not attempt to do so, and if you do, you do so at your own peril.
That said, *irrespective of this video*, it certainly seems like policemen these days use deadly force in too many situations. I have family who are retired policemen, by the way.
I think that if a policeman shoots and kills someone who later proves to have been unarmed (and also not pretending to be armed), they should automatically loose their job and their right to carry a weapon as a peace officer. There may need to be some latitude with that policy for extenuating circumstances, I admit.
Look at it this way: I have a job. What I do for a living is irrelevant.
If I make a mistake at my job, my employer has the right to fire me.
In my mind, if my mistake entailed accidentally killing someone, then I deserve to lose my job. Certainly I don't deserve to be trusted with a weapon, for a living.
Cops must defend themselves, and they have a rotten job that at many times a day is personally hazardous, and they deal with the lowest scum in society. This is everywhere, in every country. I respect the hard job that they have.
I also recognize that none of them were conscripted into service - they chose a career in law enforcement, fully aware of the dangers of that occupation.
People make mistakes, and cops are people too. All I am saying is that if their mistake entails shooting and killing an unarmed suspect, they need to lose their jobs for their error.
Again, I'm not commenting on this video specifically. That officer's actions must be judged in the context of the rules of his/her jurisdiction, training, and circumstances leading up to where the video begins.