The case you cited isn't just a civilian killing a cop at a traffic stop or during a random crime. It's a targeted assassination of two police officers for politicial reasons. It's more terrorism than crime. This makes it very newsworthy.
Equally, if a cop went out purely to kill some black men for reasons of political revenge, that would be newsworthy in a way that a random death at a traffic stop is not.
The status quo, however, is that random traffic stop deaths of white guys are not newsworthy, but random traffic stop deaths of black guys are national news. That racist double standard is what's being called out.
selectively reports what happened, and only if it tells the right narrative and/or generates clicks, yes.
Mass shooting where 3 innocents die = clicks and correct narrative and will therefore be reported.
DUI crash where 5 innocents die = boring, wrong narrative; no report
Civilian kills police officer = boring, wrong narrative; no report
Police officer kills civilian (esp. with different color skin) = clicks and correct narrative and will therefore be reported