When my lifes on the line though, the only law I abide by is Darwinism. I believe my right to live supercedes anything ever written by a politician.
While the right of self-defense seems to have become somewhat endangered in some countries, we have it here, in every jurisdiction.
That's not the issue at hand. When the armed robber accosted the citizen, he put the citizen in immediate jeopardy, and the citizen had the right to defend himself. He reportedly did so successfully.
What the Police Chief, the DA, and the Grand Jury contend is that the citizen, having successfully and lawfully defended himself and incapacitated the robber, shot the robber in the head after the injured robber, having been disarmed, no longer posed an imminent danger of death or serious bodily harm to the citizen or his spouse. They have concluded that while the citizen's initial actions were justified, the citizen's life was no longer "on the line", so to speak, when he fired the second shot.
They do not have the final word. Whether or not the citizen could have or should have been able to discern in those split seconds during the struggle that the robber no longer constituted an immediate threat will be decided by a trial jury, unless the defendant decides to plead guilty to a lesser charge, should he be given the opportunity. None of us are charged with making that judgment, nor have any of us seen all the evidence, heard all of the testimony, or been instructed in the law by the trial court judge.
As Sam1911 said, the defendant has some worried days ahead of him.
Regardless of how it turns out, this kind of thing has happened before and it will happen gain, and we need to all be extremely mindful of the fact that deadly force is lawful when and only when one is in immediate danger and one has no other alternative--not when one believes that danger might present itself later, and not after it has passed.