I'm NOT agnostic about unicorns, ferries, world ending prophecies or gods. I'm an anti-unicornist, anti-ferriest, and anti-theist.
I believe they're all made up nonsense. That is to say, I think they belong in ferry tales and children's books and don't exist - nor are a part of - our reality.
What's my rational? What's my evidence you ask? Well, it's very simple: Things for which there is no evidence and things which don't exist - are categorically identical. There is no way to tell the difference between the two. And indeed there's no good reason to think there is a difference between the two.
Or, if I may boil all this down into a single pithy phrase, having no good reason to believe something is at least one good reason NOT to believe it.