"I don't know if he was guilty."
You should have just stopped there because the rest of your post is essentially: "I don't really know anything except what some media outlets have told me, based on histrionic eyewitnesses and a need to fill a 24/7 news cycle with outrage, but I'm vaguely upset because the outcome doesn't match the presumptions I've come to from this incomplete information."
1) The police have every reason to try to protect their officer. One hopes that they're honest about the data they're presenting, but we've seen plenty of examples of it not being so.
2) the 'community' - from political leaders to thugs that just want to get a new TV, sneakers, and beer from a looting rampage - have every reason to try to see the situation in the worst possible light.
It's abundantly clear (from the physical impossibility of some of their observations) that many of the so-called witnesses are lying. It's possible that the cop is lying.
The ONLY people that ostensibly saw and heard every viewpoint and piece of evidence were the grand jury and the judge. It may not be perfect, but that's as close as we can get to objective.
To be "upset" about something from as peripheral a pov as we have is ludicrous. (To loot a store, or burn a restaurant in 'outrage' is idiotic.)
PS I fail to see how this is "tech news for nerds"?