There are powerful people pushing the race agenda right now, with the goal of distracting people from the real issues involving law enforcement and government abuse in general. You seem to be falling for a tactic that news likes to use: Flooding the front pages with fluff that they know will distract a large portion of the populous.
I do not think the discrimination is as large as they say it is. African Americans commit more then there share of crimes vs the relatively small size they represent (US as a hole, maybe there is major racism in some city's) In some city's police rarely even pull over black people because they are worried about getting shot (Bad parts of Detroit to name one).
In addition police look at lists of crimes committed by there populace; what they see is that blacks/Hispanics commit more crimes then do Jews/Europeans/Asians/ext, this makes it so when a black person starts yelling and getting mad and shaking there arms at racism, or worse walks twords a cop, the cop may be inclined to shoot.
Also the prison population of the USA is larger then every other country on earth, more then even china. The USA owns ~25% of the worlds caged people, yet only has ~5% of the worlds population.
Now you could say the explanation, is that the US citizens commit more crimes, but this is obviously easy to disprove as other country's with Lower prison/death rates have higher crime rates. Another question to ask is: Do the higher prison rate cause are lower crime rates, and the answer would most likely be no. Iceland with one of the lowest prison and cop abuse rates in the world also has one of the lowest crime rates. (Could be other reasons like low population or dare I say less violent people)
TL:DR. 1: The US is killing to many black people, but they are also killing more white people then any other race, in raw numbers. But everyone can agree cops in the US kill WAY to many people of all races, then they should! 2: the news floods the market with crap to get you to not see the more important things.