First, you already do.
Second, since God is an integral part of the whole Noah's Ark story, the acceptance of Noah's Ark is an implicit acceptance of God. Once that's done, then all the objections to the story can be "rationalized" awy. However, you're doing it backward. The impracticality of Noah's Ark doesn't mean the non-existence of God, but the non-existence of God would render the whole account of Noah's Ark (if one wanted to be a biblical literalist) as fanciful as you claim. Not arguing either way for the existence of God here, Skin. Merely pointing out that the only way the Noah's Ark story could work (not as as piece of fiction, btw) is with the implicit understanding that an all powerful diety exists. Naturally, if you discount God, it would rationally follow that Noah's Ark is merely an allegory.