Participating in illegal wars is criminal. The honorable soldier refuses to carry out an illegal war. Petraeus refused nothing on principle.
As Dave Lindorff reminds us, we have had honorable military officers in the recent past, such as Admiral William Fallon. In 2007, when he was head of Centcom, in charge of U.S. forces in the Middle East, he told the Bush administration there would be no attack on Iran "on his watch." At the time, Fallon also reportedly called Petraeus "an ass-licking little chickenshit" to his face.
It could be argued that Petraeus' actions have not been war crimes so much as monstrous incompetence. That would go a long way toward explaining why our spy chief couldn't keep his email secret. Either way, we'll be paying his pension for a long time. Feel better now?