You know what I don't understand? And this is just an observation from what I've read on various forums, mind you. People are always quick to chime in when it comes to Christianity or any of its various flavors, but if Graet had noticed quotes from the Quran being quoted, would he have been so eager to post the same thread?
I can't speak for Graet, but I sure hope so! As westerners, Christianity is shoved down our throats everyday whereas the same doesn't really happen with Islam. Maybe that's why you've experienced what you talk about.