[user104658]

If she has genuinely completely changed her beliefs, which she claims is the case and appears to be the case, and can probably be verified rather easily by experts (she's a 21 year old who has had no formal education since 15 - not Natasha Romanoff) there's no rational reason to not allow her back into the country, and even to consider her worth as a possible asset against Islamic extremist trafficking and grooming.

I would feel differently if she had been an active combatant in ISIS but she was groomed as a "wife" (sex slave and baby producing machine) and kept in a camp.

I fully understand that the general public doesn't understand how brainwashing and grooming works, why teenagers (children) are especially vulnerable to it, and that even people who become genuinely dangerous because of it are still themselves victims in another sense...

...but that's why the general public's opinion shouldn't come into these decisions. But it does, time and time again, not because of safety, not because of science, but because of political populism.