In the Zimmerman case, the issue was not “common sense.” It was about reasonable doubt. In order to convict Zimmerman, the prosecution would have had to prove that Zimmerman was lying about being attacked by Martin. Prosecutors could not prove that.
In the infamous Walter Scott case, the issue was not the non-functioning brake light. The issue is that Scott fled the scene on foot after being stopped, then fought with the officer when the cop caught up. The officer shot the fleeing Scott in the back, which was probably illegal. But Scott was not summarily executed over a brake light.
As for BLM: There are videos of a BLM march in Minnesota during which the crowd is chanting “Pigs in a blanket, fry ’em like bacon.” And in an anti-Trump march earlier this year, a woman wearing a BLM jacket, addressed the crowd and shouted: “ “And we need to start killing people. First off, we need to start killing the White House. The White House must die. The White House, your fucking White House, your fucking Presidents, they must go! Fuck the White House.”
IOW, rhetoric coming from BLM is at least as inflammatory as anything the KKK has ever produced.