Bingo, good post. ISIS has always had more money that jihadist fighters. Most are tribal militia men from Syria and Iraq that just want to be paid.
The Kurds and ourselves understand that we now need to win the peace.
I assure you the YPG/JPJ wanted no part of releasing any without careful interrogation.
The foreign fighters were all totally evil people. None deserve to be released, ever.
Conscripts? Some had the choice, join and fight or die now.
Some of the locals did it for the money, found out quickly they made a mistake but could not leave without being killed.
Some young children were forced to support and brainwashed.
No, I have no real sympathy to any of them except the children and forced at gunpoint conscripts (many of them found a way to escape).
We do have captured records for most of the ISIS supporters. It will follow them forever. If their real identity is know, they will be exposed.