Black males make up only 6% of the population in America, but they commit 54% of the violent crimes. That means that cops have contact with black males more than all of the other races combined. Cops are also more likely to be killed by black males. Taking these facts into consideration, it's only reasonable that cops would be more wary of black males than the rest of the U.S. population, and more inclined to use force. It's also reasonable that black males would be involved in more shooting that are questionable.
The problem in America is not racist cops, but black crime that is out of control. This problem will not be solved anytime soon because Americans are too politically correct to properly identify the problem.