Yes, muslims have a harder time integrating than other groups. I believe this has not neccessarily to do with the muslim nature (although religion might have its influence) but with their numbers. They arrive, settle in a poverty district, find out that their neighbours are arabs, along with the grocery store owner, 3 mosques around, can go chat in a tea shop, no need to adapt. Italians or Russians arrive, settle in the same district, yet they don't understand arab grocery guy and don't become friends with arab neighbours. They will strive to adapt into the country faster to get out of there.