You can always look at the worst offenders in a group - in this case, conservatives - and hold them up as an example of what you think the entire group is like. I mean, that's how racism works, right?
The same could easily be done of Democrats who've conducted themselves in a really heinous manner: tweeting the (incorrect) address of Zimmerman's parents, offering a bounty for Zimmerman's capture "dead or alive", etc. That doesn't mean that Democrats as a whole should be judged by the conduct of the New Black Panthers, Al Sharpton, or protesters turned looters.
Sure, there are Republicans who've obsessed about Martin's background and made big deals out of stupid, irrelevant stuff like the fact that he smoked weed or thought taking a photo of himself with fake gold teeth was cool. But the majority of what I've read from conservative sites - not just the most outrageous stuff selected by the liberal outlets you probably read - is about denouncing and debunking yellow journalism and the rush to judgment, defending the gun laws involved, and fighting the initial narrative that that was a cold-blooded, race-based murder that is symptomatic of a broader, more universal issue of whites (or "white Hispanics"?) killing blacks because of their race.
As far as standing your ground goes, I don't think you understand the legal principles involved. Following someone around for whatever reason is much different than physically assaulting them, telling them they are going to die, etc. I'm not saying that I believe Zimmerman's account to be true, only that it is possible that it is true, since no evidence revealed so far disproves it.
I'm not familiar with the last case you list, but I agree that blacks get the short end of the stick in the justice system. For example, I'm not sure if you are familiar with Cory Maye, but he was a libertarian cause celebre for quite a while, with Radley Balko, formerly of Reason and the Cato Institute, doing the heavy lifting in breaking and publicizing that miscarriage of justice.
appears to imply that, absent such evidence, a white or otherwise non-black man (there is some controversy as to whether Zimmerman should be identified as white, or Hispanic, or both, although no one seems to be claiming he is black) claiming self-defense after killing a black man is simply to be taken at his word. It is hard to resist the thought that race matters here, for who believes that, had an adult African American male killed a white teenager under similar circumstances, the police would have taken him at his word and so declined to arrest him?
