America isn't a threat to the Sunnis. If anything, we're the only thing between them and violent retribution by 80% of Iraq's population. Neither the Kurds nor the Shiites will be as gentle as we are, so now's the time to make nice. They know damn well that if we leave, and they're still causing trouble, it will be civil war, and one they're not in much of a position to win.
Zarqawi and some of the extreme Saddamists had managed to convince these losers to go off the cliff with them. These guys are just figuring out were they are being lead and are trying to excape.