Religion

Faith is the foundation of fundamentalism. Without it there would be no such thing. Fundamentalism isn't a modern phenomenon. It was the default condition prior to the Age of Enlightenment when the idea of enforcing fundamentalism by law was questioned. The only thing that's modern about it is some have retreated to fundamentalism as the world grows more secular.

Organized religion has always been about control. Nothing has changed really other than at least some people in this world have a choice in the degree by which they are controlled. Anytime someone tells you how to think and act based on some metaphysical and mythological idea of reward and punishment, you are under their control.