We can't prove reality. I reference of course to the field of epistemology with Hilary Putnam. You put faith in that the hands before your eyes are really there and not just a figment of your imagination. You'd be amazed at how little science knows. We don't even know how the pyramids were built 😛
The reason religion is such a popular myth to be waging war against is because it's the most known one. Few know that Plato questioned our idea reality and many more after him. René Descartes through the application of the cartesian technique, thought up by him, proved a reality, but not necessarily our.
Another popular myth that few care for is the Nostradamus prophecies, because they are neglected as coincidences by most because of our supposed understanding of time. That time has to be linear or we'd know otherwise 🙂
The point I am trying to have made is that why care for that myth at all? Reality is what you perceive and if someone perceive God as reality then you are in no position to claim him false. Your reality might be false and God might be the one thing no artificial reality can keep out 😛
For all we know, God is the most real thing in this dump of a reality 😄