Zimmerman was not found "innocent" but rather "not guilty." But the jury carefully examined and reviewed evidence as presented and determined there was not enough there to, beyond reasonable doubt, convict a man of second-degree murder. It happens every day in courtrooms across the country. The reasonable doubt standard is to protect innocent people from paying a steep price for crimes they did not commit. It is not to provide cover to allegedly "favorite" citizens whose actions meet or exceed the reasonable doubt standard.
The events that transpired between Zimmerman and Martin that led to the boy's death are indeed tragic. But the politics conducted over that Martin's corpse are even more disturbing, especially when the president of the United States is fully engaged in such morbid politics.