I keep trying to understand. Why isn't life precious anymore?

BREAKING NEWS: "An unarmed man killed by a white Oklahoma officer who was responding to a stalled vehicle can be seen in police video walking away from officers and toward his SUV with his hands up before he approaches the driver's side door, where he drops to the ground after being shocked with a stun gun then fatally shot." I know this is another in a string of police killings of innocent citizens and again between a white officer and a black victim, but it still bothers me--e v e r y t i m e. The conflict for me is--I respect the police; I appreciate the dangerous situations they are placed in; I believe the majority are still good, law abiding people who love other people even beyond their family and friends, and probably in the whole of all police interactions, these situations are small in number, but isn't even one too many? In some of the cases I've read, the situation was unclear either in the real situation or in what the new presented, so it is hard for me to make any comment on those as I may not know all of the information, but this latest one has hit me. WHY? Oh, my God, why? What excuse could there ever be to shoot an unarmed person who had already been tased? Are we as humans so out of control of our own emotions (anger being the most volatile) that we cannot move past disrespect of us (if that even occurred) or do we value others so little that we even feel it is ok to hurt another? It is not just police and authority figures, people keep killing people over arguments, road rage, differences. I don't think I should have to be an idealist to believe we don't have to behave on the defensive, reactive, harmful. My personal experiences differ so much-strangers I've met in the US, in other countries, have been friendly, helpful. Most people I know are not extreme-they are hardworking, parents, friends. They have hobbies, interests, jobs, experiences. I feel that the majority of people are just humans trying to live there lives to best that they can with joys and without added stresses. I know there are people who are jerks and there are people who are not. I like to surround myself with people who are not. I actively avoid conflict, not because I can't stand up for myself and what I believe. I just choose carefully those issues worth it to me to make those waves. It is not worth it to me to get worked up if someone cuts the line, is careless driving, calls me a name. Ultimately, they hold no power over me. I digress... Anyway, I hate that any person chooses to take the life of another. There may be a few exceptions like self defense, but generally it's simple-Don't kill. And why should power or authority make it justified?