I think people have religion in their lives because of how they were brought up in general. But there are a plethora of reasons why each individual would chose to be religious, be part of a religious group, have a belief in a religious book, and believe in a God or Gods.
It's just like why we woke up from a cult. We all woke up for different reasons, some of us have the same reasons, but different things led us to the light bulb moment.
Kate xx