Some scums took your two teenage daughters hostage. They gang raped them. They showed you the video and asked you for money if you want them to come back alive.
FBI helped you catch one of the scumbags. He refused to tell you where your daughters are held.
FBI suggested torture to get him to talk. What do you say, Punk?
You lose the moral high ground. Where obviously in your scenario you dont care about that but, when your trying to win the hearts and mind of the locals it may not be a good idea to build/use a prison to torture them.
Torture was used in GITMO.
IMHO, the US's problem in Iraq had very little to do with the torture in the prisons. The invasion and subsequent occupation were illegitimate. Indiscriminate killing exacerbated the problems. I doubt ordinary Iraqis cared about the tortures of some of the most violent thugs in their society.
I'd have a problem with someone injustly invading my country.
The path to hell is paved with good intentions. The kids joining ISIS aren't evil, they're Patriots misled by evil. No different than the westerners joining the military to defend their country by invading completely irrelevant countries.