The outcry about police comes from the fact that unlike black civilians, they are the ones entrusted and employed to protect the people, so when they cross that line, it is considered a much worse betrayal.
In terms of police...pretty much this. People make more of a stink about police engaging in that behavior because they're the ones who are supposed to be preventing it.
It's along the same lines as if a news story came out about a fireman playing around with gasoline and accidentally catching a building on fire. People would be more upset than if it was a story about some regular dude doing it.
Who says no one speaks out against violence within the Black community?
There is an outcry, but there is a huge disparity in terms of media coverage and social media outrage based on the races of the folks involved.
Look at the media circus that takes place for some of the cases. (and then the almost non-existing coverage for others)
Roderick Scott (a black adult male in his 40's) observes white 17 year old Christopher Cervini engaging in what he felt was "suspicious behavior". He calls the cops, and then, ignores there advice to simply keep an eye on it from his window, and instead, grabs his handgun, and decides to play cop. The exchanges ends in Scott shooting and killing Cervini. Scott is acquitted in accordance with stand your ground laws.
(the notes about this story sound quite a bit like another news story???)
Gwen Jenrette observes a teen breaking into her home on her remote security feed, calls the cops...and instead of waiting for them to get there and handle it, she decides to go home, and ends up shooting the teen as he's trying to flee
(it got a blip in a few local Miami newsapers)
Now, compare that to the massive outrage/outcry we saw in the Zimmerman case (even though, aside from the races of the 2 parties being reversed, is almost identical to the Scott/Cervini case)
The fact that 99% of people probably never even heard of the first 2 cases listed, yet Zimmerman is a household name, illustrates my point very well.
To be clear, there should always be some outrage and public discussion when someone shoots someone else when they didn't deserve it, or decides to grab their gun and play cop (in spite of instructions to the contrary given to them from actual cops). However, there's no denying that there is a huge disparity in outrage and public response for the different scenarios.
Black adult shoots white kid: little to none
Black adult shoots black kid: little to none
White adult shoots black kid: DISCRIMINATION! INSTITUTIONAL RACISM! GUN PROBLEM! BRUTALITY!
I realize this disparity in outrage can be attributed to the media's quest for "covering the juiciest story that will spark the most chatter"...thus the reason why Roderick Scott and Gwen Jenrette got a blip on a few local newspapers, and are probably living completely normal lives with nobody even knowing who they are.