"Mercy" Killer Goes Free

Can someone explain to me what the difference between murder and "assault with intent to commit voluntary manslaughter" is?

And then can someone explain to me why Capt. Roger Maynulet, of Company A, 2nd Battalion, 37th Armor Regiment of the 1st Armored Division, U.S. Army - having been convicted of the lesser offence after shooting a wounded Iraqi insurgent in the head TWICE in what he himself described as a "mercy killing" - is not going to prison but instead will merely be dismissed from the Army?

WTF???

This is from the Stars and Stripes - not known to be a pawn of the liberal media:

At the trial, Maynulet, 30, was charged with a more severe crime: assault with intent to commit murder, which carries a maximum penalty of 20 years’ confinement. Panel members convicted him on a “lesser included” offense. The penalty for that ranges from a letter of reprimand to 10 years’ confinement. The verdict indicates that the panel believed Maynulet intended to kill the Iraqi man, but that the circumstances he was facing decreased the severity of the crime because he acted in a moment of “passion.”

Maynulet’s shooting of al-Haleji was captured on the videotape of an unmanned drone monitoring the mission. Maynulet did not report the shooting as a mercy killing and he made no report to his superiors other than one Iraqi was killed in action.

He later told soldiers who had been at the scene that he had shot the man to “put him out of his misery,” according to testimony.

So why on earth will this man be allowed to walk free? He and some of those under his command tried to cover up the act. He obviously knew even at the time, whether it was passionately done or not, that shooting an unarmed wounded man was truly fucked up.

Do I need to do the "hearts and minds" thing again? No - not in this case because justice is what matters here, not propaganda value. Still...wtf?

If this guy pulls out a gun and offs some poor fuck who has been in a car crash in San Francisco, as a "mercy killing", do you think they might lock him up then?