I'm of the opinion that religion and the belief in god/s was the easiest solution for mankind to answer the questions that has always haunted us. Where do we come from? What happens when we die? And the myriads of other questions related to the human condition. It's our nature to question and was totally unavoidable considering our uniqueness on the planet. The reason I believe many eventually leave their religions and even turn away from the belief in an almighty god/s after being fervent believers is simply a matter of lack of answers to even the simplest of questions. This is the one that did it for me, "Do's god exist?" One would think that if he/she/it actually exists and it was important to actually know this it would be known and unquestionable. Let's face facts it could have been easily hardwired into our brain. If your a man do ask yourself "am I a man?" If your a woman do you need to ask the question? Why do we need to question if god exists? If an almighty exists logic tells me that he/she/it would want this fact to be known, not debated. I won't delve into the other questions that mankind has pondered as we could spend multiple lifetimes discussing them.
If god doesn't exist mankind has the moral obligation to shed itself of it's primeval believes if we are to expand and improve as a species.