Being a police officer means that as part of the function of that service you are permitted to use deadly force, that is kill other people, but that deadly force must have and does have limits. In America, those limits as supported by important elements of the public and media, and as supported by the justice department, and in particular those prosecutorial agents of justice, seem to be left far too often at the discretion of the police officer, almost without taking into account pertinent factors, such as justification, necessity, reasonable action, or imminent danger.
In addition, to the wrong mindset of an "us v. them" to begin with by far too many of our police officers that engage with the public, American officers have a love affair with weapons in which these weapons by their very nature, when utilized, are extremely lethal in their effect upon human targets, as any instrument that allows multiple bullets to be shot off in the span of one second or less, is a weapon with extreme lethal force. The bottom line is that the more lethal the weapons that are utilized, and the more shots that are fired from such a weapon, the more humans that will die.
From a police perspective there is this perception that police need to have strong body armor, sophisticated toolkits, and heavy firepower in order to match or outmatch their adversaries. This type of thinking has its place, but that place is against rogue elements that for some reason or another, would want to engage the police in the first place, which virtually never happens, instead, most police are involved on a day-to-day basis with regular folk on the streets, of which, indeed, some of these people will be armed, some of these people will be dangerous, but very few of them have any desire to wish to provoke a firefight with the police.
There have been numerous protests over the last several decades, over the deliberate targeting of minorities, by the police, or agents of the police, or people acting at the behest of the police, or people given free rein to do whatever that they wish to do to minorities by the police, explicitly or implicitly. In many, many instances of the police shooting at, wounding, or killing of minorities, the aggression is on the part of the police, not of the person. The police in this country, again and again, shoot far too often, shoot far too many bullets, and shoot far too many people that don't need to be shot.
In life, there aren't that many things really worth deliberating targeting and killing a person about, which should translate into as it has in virtually every other civilized nation, into less police violence against the very citizens that they are sworn to "serve" and to "protect". Yet, in America, police clearly treat people differently depending upon where they live, the color of their skin, the way that they are dressed, how they are acting, the overall fear factor, circumstances, their own ingrained or learnt prejudices, and thereby make far too often split decisions with fatal consequences based on cursory things.
The police or their agents throughout American history shoot blacks, been shooting blacks, ever since plantation times, of which this sick mentality is still ever in play, which is, that a black man, a minority, must when confronted by the "man" immediately bow his head down, show proper respect, and demonstrate abject subservience in all aspects, or risk to get shot in the coldest of blood, and die like an animal, then left dead in the street as a warning to all others that this is no country for blacks.