They made fun of him and next batch of muslims instead going to the court to be ridiculed took matters into their own hands and executed those who ridicule their prophet. There are lot of muslims in EU, and while most of them are peaceful people large portion are young and desperate men who found their purpose and refuge in extremist views and they are time bombs. They are the invisible enemy, only way to fight it is like Americans did, to do special checks on everybody who resembles muslims. Of course, that means tolerance, equal rights and other modern values have to go out the window.
Enemy you are fighting is very determined and has values, right or wrong, but those values are strong and can't be messed with like most of other modern people who are chill, relaxed and don't take anything seriously. Those stubborn and determined are going to fail in modern society but in war they flourish. Very strong and unpredictable enemy to fight, enemy you don't understand at all.