Let's use some placeholder values. Let's say that 70% of the Muslim community in the Middle East is against ISIS. 25% are supporters, and 5% are actual members. if the 70% condemn ISIS, are the 25% changing their minds? Are they figuring it out? Or is it a, "we'll kill them and the condemnation will hamper recruiting," situation?
I just don't see any tangible results. I also don't see how they're responsible. If half my neighborhood is full of KKK members, is it my responsibility to condemn them in the local paper and possibly have my life and the life of my family in jeopardy? Ideally, maybe. Realistically, no.