Well, for many years the Muslims were pretty much contained with Sunni and Shiia offing each other but leaving the rest of us out of it.  We had our own little Cath vs Protestant bloodletting as well as the colour war going on.  With modern travel, we get to mix the pot a bit more.  Remember, Uncle Adolph told us his thoughts and plans in Mein Kampf so for the jihadist to do likewise shouldn't surprise us.