Why Do People Become (Islamic) Extremists

My friend who reposted this on Facebook commented that it does not just explain Islamic extremism.  Today in class, we talked about human nature, and the service was on our tribe, our community.  Part of our human nature is to want a tribe, community, order, and certainty in our lives.  But when we don’t question what that community teaches us and see for ourselves, we are in danger of becoming a mob of extremists. — Lisa