Many years ago people feared another institution which murdered and brutalized people because of the recipient's religious beliefs. In a town or village when they saw these people who often dressed different from the town/village citizens. These people also spoke in a different language when discussing their faith and reading their sacred texts. Villagers learned that these people who had travelled to the village/town had one focus - conversion to their faith due to the town's wickedness for embracing the devil/satan/evil. Citizens also learned over time that these different people usually dressed in black would befriended people in the town to learn more about the other citizens and how their town was run. Who was the leader/mayor, government, and so on? You can read about their brutality which was far more evil than the current terrorists of extremism in Islam in such books as the Foxe's book of martyrs. These terrorists were the Roman Catholic Church and the period has become known as the Roman Inquisition of the 12th through 17th centuries.
Why bring this up? Because the parallels are serious and the method of protection for oneself should be also. If you saw these killers you should identify them quickly and then remove their the threat to your society -- you don't protect the people by ignoring the obvious signs.
This is a pattern repeated down through out history in many if not most countries by different religions or forms of humanism. People too often and quite easily kill other people for the unwillingness to join the power holder of the moment. Whether it is genocide in Africa, Korea, Cambodia, Thailand, USA, France, Russia, China, and so on. Human beings kill other human beings and if you want to survive and have the norms and way of living in your culture and society the least unaffected by the murderers you HAVE to immediately identify the threat and neutralize it either by locking them away or killing them. Peace through strength not ignorance.