The whole point of religion is the same reason philosophy and science exist.
All three exist to solve the big questions in society, but they do so through different means; (in a VAST oversimplification) religion looks at metaphysics, science looks at mathematics and philosophy looks at behaviour.
People are free to choose whatever they want to justify the world being the way they see it. I personally find philosophy the most interesting because it helps you understand that you have no real way of knowing if what you perceive is "truth". Combined with psychology, you start to see some forgeted up stuff about the way we live.