They lose their moral compass. How else could anyone accept a system that believes shunning and allowing one's children to die for lack of a blood transfusion are good things? Only people that trade in their conscience to some degree for whatever consolation it brings them would do such things. They key is to what degree. Some are worse than others, but all are affected.
Not sure how you left, but I know it took some personal hard knocks for me to wake up. I consider myself lucky because of that.
d4g