The Kentucky Attorney General had the authority to charge or not charge homicide offenses. Having not reviewed the facts, hard to say whether his decision was righteous. I do note the City of Louisville paid out $12 million in a wrongful death civil action, which does not necessarily equate to criminal conduct.
The prosecutor controls the presentation to the Grand Jury. It is a one sided exercise. So, I would not place too much stock in the Grand Jury's rubber stamping.
We are a tinder box. Many Americans feel that we have two different application of our laws - one for those who have power and privilege, and another set for everyone else.
Again, effective leadership and tone at the very top would help. But, we have a President who is pushing us towards an autocracy, and who delights in fueling discord and division.