A religion is a tribes rules and collective memories rolled up into an all inclusive world view. It’s passed down from generation to generation until fiction and mythology become fact. Once it becomes the sacred word of god, then we call it a religion.
And that’s why it seems so real from the inside. It’s a complete system with all the answers because it has been tailored to fit the tribe by countless minds over many generations. And it flourishes because it promotes the tribe’s best interest. Not the individual’s interest but the tribe’s interest.
But religion can only become rooted in a child’s mind in the absence of conflicting information. That’s why it’s so important to indoctrinate a child into a religion early in life, before they can learn about the real world.
Indoctrinate them early and sufficiently and they will reject all non religious facts as the work of the devil and pass that belief system on to the next generation.