I've just written an article that's loosely a response to this one. It's tentatively called, "Atheism and the Burden of Refuting the Preposterous."

I think you miss the point of the celestial teapot analogy, which leads you to miss a third option between agnosticism and this longsuffering atheism that takes on the same burden of proof as the theist.

The third option is to dismiss what's preposterous. You reject the preposterous without bothering to consult all the evidence because you reject it out of hand. You dismiss the absurd and you scoff at the notion that you should take it seriously. Indeed, you'd flee and sever ties with the proponent of the preposterous, because you'd be in your rights to suspect that that person is trying to pull the wool over your eyes.

This raises the question of whether theism is preposterous, which in turn raises my point about the historical and cultural relativity of that presumption. Relative to modernity, theistic religions are as empty and preposterous as the possibility that there's a teapot orbiting the sun near Mars. Relative to medieval Christendom, atheism was preposterous.