I've tried not to wade into the Zimmerman matter, because honestly I think this guy exercised poor judgment. He's not a shining example of goodness or a great example of a sterling neighborhood watch captain.
Evidence points to Trayvon Martin doing things that might include casing houses and committing burglary. If suspicion alone could convict a person, Martin would probably be in jail. However, suspicion can't convict a person, nor do we incarcerate people long term unless we can prove they did something wrong beyond a reasonable doubt. All we can prove about Martin is that it looks like he'd exercised poor judgment a number of times in his life.
You've probably guessed where I'm going with this. Zimmerman exercised poor judgment. Not in having or carrying a gun, that is his right under the 2nd amendment and the laws of Florida. I think he exercised poor judgment in following a suspicious person in his neighborhood. As part of our neighborhood watch in my own town, I call the police and make reports. That's it. It's not my job to pursue. I think Zimmerman chose poorly in doing so.
The outcome was really awful for Martin. Evidence points to him attacking Zimmerman and hitting his head against the pavement at least once (once can kill a person, by the way). He didn't deserve to be killed even if he was casing houses and was a burglar. He didn't even deserve to be killed for attacking Zimmerman. Once Zimmerman felt he was in danger of death or great bodily injury, however, he was justified in using his firearm.
"Justice for Trayvon" doesn't mean Zimmerman goes to jail for life. Justice for Trayvon means that authorities look at the case. If there's cause, justice means Zimmerman is charged and tried. If a jury says there's not enough evidence to convict Zimmerman, justice means Zimmerman is acquitted and walks free, because just as it did with Martin, our justice system errs on the side of caution.
The police and DA of his county initially felt that Zimmerman's story was consistent with the evidence to the point that they weren't going to charge him. National outrage that would not have even existed had the media gotten the facts right and reported Zimmerman is Latino*, caused the Federal government and State government to push the matter. A jury has now decided there isn't enough to convict Zimmerman. So the police, DA and a jury all decided Zimmerman may be guilty of making poor choices, but he's not guilty of murder.
Justice doesn't mean Al Sharpton (who is notoriously wrong in cases like these--remember Tawana Brawley or the Duke Lacrosse team?) gets his way. It doesn't mean we do whatever the media demands. It doesn't mean we bow to the demands of a bunch of twitter thugs.
Justice has been done.
*As an aside, people making this about race are completely wrong. That angle only has life because the media made it about race.