It’s a tough position for them. Snitch, and you’ll get beheaded. Hard to trust someone to protect you when your current oppressors are in place precisely because that someone reneged on protecting you.
Read _American_Sniper_; gives a good account of how long it took to gain the trust of the locals that they would turn on the “terrorist next door”. And then we left.
I’m all for going in and eradicating ISIS before it spreads thru the region (there’s nothing else to stop it, and both morally & diplomatically we are obligated to), but I’m afraid it will have to burn itself out - which will take generations.