If they are muslims, while they might not be a threat to the United States, they definately a threat to the infidels.
After all, the guys that flew the planes into the World Trade Center were actually Southern Baptists masquerading as muslims.
The 9-11 hijackers were mostly upper-class Saudis who hated American. These guys are from a group fighting the Chicoms. Why would we hold them as enemy combatants?