All you need to remember to distrust the media's reporting is that they all keep referring to Zimmerman as a Neighborhood Watch volunteer, when he wasn't - he never bothered to enroll in the actual program, nor did the Homeowners Association of the complex where he lived. It's like picking up a Boy Scout uniform somewhere, and portraying yourself as a representative - it's deliberately creating a false impression of who you are, and it's despicable, IMO. The reporters and editors are aware that Zimmerman has no right to call himself a Neighborhood Watch volunteer, yet they continue to credit him with an aura of legitimacy he never earned, nor deserved.
Also, the Zimmerman - Martin shooting was about race, in Zimmerman's mind, at least. The fact is that he called to report 'suspicious' people very very frequently, and they were invariably black people. It's hard to credit that white people never did anything he found suspicious, ya know?
I understand [and agree with] the frustration over agitators who scream 'racism!' every time a black person is accused or arrested or killed, but in this one incident, it appears to be justified.
I also understand and agree with the outrage at the choice of crimes that get publicized, and would suggest that maybe sharing that with the editors of the newspapers involved [or leaving comments after the stories] might be helpful. Or not - but it's what I do, anyhow.