The second biggest branch of Islam (Shia) is every bit as anti-ISIS as the west is. Same could be said for other groups (Ibadi, Kurdish, etc). It is worth bearing that in mind.
The vast, vast majority of musilms are anti-isis. Just as well really as if they weren't, and things were really as some on here say they are we would have a serious problem because there's a billion of the buggers.