Some people think that evidence should count for less than "alternative" evidence, that you don't need math to understand the world. I used to think they were all called "Creationists" and then I find even in atheist communities the same types of people abound.
Conspiracy theories aren't being ignored because they are fact, they are ignored because they can be debunked. They are not fact, either in part or whole they are wrong. Usually this can be proven quite easily. Ancient writings aren't in themselves evidence of anything other than ancient people wrote stuff. It takes more critical thinking to determine what was really going on. It's amazing to find science deniers here on atheist nexus.