no its exactly the same because if you leave you have to punished
and they didn't join "the enemy" they went to fight Assad, something the US government endorsed at the time
It's similar to the situation of say the Abraham Lincoln Brigade of American anti-fascists that fought in the Spanish civil war. They found out war is a dirty business and you never know who you are really getting into bed with. Now they want to come home.
They've had enough of it and want to rejoin western society. Plus they are a gold mine of operational data and other intelligence. It's foolish to take on an inflexible attitude and let emotion dictate your actions.