The Grand Jury didn't choose not to indict Darren Wilson. The St. Louis County District Attorney made that decision. For the uninitiated, let's take a look at how the grand jury system works.
The first thing to remember is that the system is stacked in the prosecutor's favor. There is no voir dire when a grand jury is selected. Due to time concerns, most of the folks who serve on grand juries are retired or hold jobs that allow them to take chunks of time off without reprisal. In many jurisdictions, grand jury commissioners are appointed and they select the grand jury - little need to worry about the grand jury reflecting the diversity of the population in that scenario, however.
Grand juries originally were envisioned to screen cases so that citizens accused of a crime wouldn't face public shame if there was insufficient evidence to go forward. They still serve a screen purpose today - and that's just what St. Louis County DA Robert McCulloch used the grand jury for in this case.
Prosecutors hate bad publicity. But what they really hate is having to make a controversial decision that's going to piss off folks that might vote for them. In a case in which folks are going to be angered one way or the other, the DA looks for someone else to take the heat. And that "someone else" is the grand jury.
The prosecutor is the only person who puts forward evidence before the grand jury. Yes, the (potential) defendant might testify, but only under certain conditions would an attorney take that tack. The prosecutor calls the witnesses, submits the evidence and pushes the grand jury down the path he wants them to take.
Then, once the grand jury announces its decision, the District Attorney can tell everyone within earshot that it was the grand jury's decision to proceed or not. Of course the general public never hears the prosecutor urge the grand jury to indict ("just think of the message it would send to the community if you didn't") or "do what you think is right."
The entire process in the Ferguson case was a circus from the beginning. Most grand jury presentments last but a few minutes and consist of little more than the prosecutor summarizing an offense report. Whatever evidence is submitted is never disclosed - unless the defense attorney can convince a judge that someone is playing fast and loose with the rules.
Mr. McCulloch dragged out this process and did everything in his power to color the facts and bury the case. The case took almost a month to present. He called 60 witnesses. He released all of the information presented to the grand jury. His press conference consisted of him blaming Michael Brown and the media for everything.
He's the one who decided to announce the decision at 8:00 p.m. He's the one who decided to give the people hours upon hours to stew. He's the one who decided to smear Michael Brown's name before the national media.
But we are to believe that any anger folks are feeling about the no-bill should be directed at twelve citizens who did as they were told?