In the immediate aftermath of last week's white nationalist terrorist attack on two mosques in Christchurch, New Zealand that took the lives of 49 people, U.S. president minimized the scale of the problem, proclaiming that there is no systematic issue: “I think it’s a small group of people that have very, very serious problems.” This, however, is exactly the kind of denial and deflection that the West had criticized so forcefully when it came from Sunni Arab countries after 9/11. Ever since the early [aughts] ​2000s, the U.S. and Europe have rightly pressed a number of Sunni Arab countries to...