Internet is cute, knowledge is great, but it is an idealist, far from reality, relation to physical combat. An individual, as you mention, may not need to know Krav Maga or have a gun, but the ones protecting you do. And lots of them. And believe, good thing they do. Because when terrorists attacked The Bataclan in Paris, FB or Twitter messages did not stop the massacre, but more guns did. People in the US can walk freely and not worry much because of their government taking the war back and keeping it overseas. That is the great fear in Europe. People not regular to Krav Maga/guns, waking up to a violent confrontation, on their streets.