When they immigrate to civilized countries, many of them take their backwardness and violence with them and refuse to assimilate. Their religious leaders are always threatening to have their religion take over the world and either enslave non-believers or kill them.
What to do. We'll see if this latest unrest in Egypt leads to a real semi-democratic government or just more of the same. Most likely more of the same. (Or Morsi of the same). There are some experiments going on (Iraq, Egypt) that might foretell the future of these peoples and if they'll be able to adapt to modernity and throw off their barbarity. If they can't, at some point the civilized countries of the world might have to think of a way to permanently segregate these people from the rest of the world.
They will claim they invented math. The arabs before Big Moh were actually sucessful traders. They were semi-peaceful and got along well with their trade partners. When Moh took over that all changed. Gotta keep the masses illiterate so you can control them.