A metaphor for what?
The objection here is that same as with the use of the word "allegory." A metaphors is "a figure of speech in which a word or phrase literally denoting one kind of object or idea is used in place of another to suggest a likeness or analogy between them"
With a metaphor, we have something that is representative of something else, and we know what that something else is. If we're saving for a rainy day, we're saving for a time when things are not as good, assuming that we like sunny days better than rainy ones.
How about the four corners of the earth? What aspect of the globe do the four corners represent?
If you read the Bible with a confirmation bias, namely, that nothing in it is wrong and its god is never immoral, then you make corrections to force that be the case. From that perspective, you assume that the Bible writers, under the direction of their god, knew that the earth didn't have corners, and so you call it metaphor despite there being no indication that the description wasn't meant literally.
The unbeliever doesn't do that. We take the words at their face value. We read the Bible like we read everything else, and like you read everything else. If you were reading the Quran, you wouldn't be doing all of the housekeeping you do when reading your Bible. You'd see something like a self-contradiction, an error of fact, or an immoral act by Allah, and you'd call it that just as the unbelievers here are doing now with scripture from the Christian Bible.
Hockeycowboy said, "Everything about Genesis is correct, when not looking through muddied glasses." Isn't that exactly what we would expect the Muslim to say to us about his holy book if we identified inconsistencies in it?