Of course more black guys are killed by other black guys. More black guys are killed by cops than people realize... the point I'm trying to make here is that this has actually been happening for a long time, but nobody noticed until it was recorded and spread on social media. MOST of the deaths associated with black guys vs cops are because there is a legitimate threat and the cop was defending himself or others.
This, like many other issues isn't clear cut - it obviously depends on the situation. Really, this isn't a "who killed who" issue, it's an issue of who cops are shooting and when is it necessary. I'm willing to bet the majority of the time anybody is shot by a cop it's fairly necessary, but there are many cases where it's not - hence the outrage.