Instead of bombing ISIS/ISIL controlled areas, simply make high concentration LSD and mist the area with it for a whole week.
At best, they trip out and realize they are terrible people, at worst, they start having a bad trip and attack each other.
Music or anti-violence propaganda could be used simultaneously to provide a lasting mental impression.
Air drop some healthy food/beverages with messages of peace so they don't have to worry about sustenance.
I mean, why not? This would be hilarious for approximately all eternity.