I'm a black guy and former cop. This guy was wrong and deserved to be sentenced. That lady should still be alive. The problem is that so many others should be guilty, too.
I'm not the judge/jury but based on personal experience, not everyone is cut out for "the job". Yeah, we were trained to survive, yell "stop resisting", and to say "I feared for my life" but there are intangibles that a lot of these cops just don't seem to have. Balls, if you will. Lethal force should be the last resort after you tried talking and even fighting if it comes to it. Sometimes all you can do is react but use the gun LAST.
And another part of the problem is US. As black people (and maybe white, I don't know. Can't speak for them.) it's like we HAVE to be confrontational. We have to show that we're not bitches. We have to be there hardest. Other races are paying attention. They're scared of us. Somebody else could be paying the price for something another person did.
There was a viral video a month or two ago from my area where two guys were fighting.. One guy was knocked to the ground and the other guy proceeded to stomp on his head and neck with the full weight of his body. Nobody helped the man who was stomped. Nobody called 911. Everyone just walked away as one guy said "Y'all know how it is. When a bunch of gorillas get together in the jungle, it's gonna be trouble."
That kind of brutality is common. I remember seeing stuff like that first hand, even as a kid. We can ask other races to show us sympathy but damn. Sometimes we're our own worst enemy. Everyone is watching, now.
I think another problem is how too closely knit the black community feels it needs to be. This definitely doesn't go for all, but I feel too many side with other black people just because they are also black. It doesn't matter how the facts present themselves, they believe the initial story the media tried to push (which is an issue in itself) and refuse to accept that it may have happened differently as more details emerge.
Two examples that spring to mind are Michael Brown, with the "hands up, don't shoot" lie, and the Treyvon Martin case, where his family and the media only published pics of him that were 5-6 years old from when he was 11-12 and initially claimed Zimmerman was white. Which led many to believe Martin was a very young boy shot by a white man, not a 17 year old, nearly 6 ft tall, young man shot by a Hispanic. Having a "snitches get stitches" policy also isn't a great way to clean up your local community and just allows crime to spread.
As for police shootings, we know from the raw data the problem is greatly exaggerated, though there are definitely cases where the cop should have been convicted. The problem is we focus too often on those, maybe because many of them are publicized, but seemingly not at all on the ones where the cops are found guilty of wrongdoing.