By Bret Stephens /The New York Times There is a measure of comfort to be taken in the fact that Sunday’s terrorist attack at a Hanukkah event at Sydney’s Bondi Beach, which left at least 15 people dead and many more injured, also produced a hero. A man described in news accounts — but not yet confirmed by The New York Times — as a local shopkeeper named Ahmed al-Ahmed single-handedly disarmed one of two terrorists and survived being shot twice, in a scene that was captured on camera and has since gone viral. That act of bravery not only...