If the story in Genesis 3 was deliberately made up by people who did not believe there had ever been a talking snake, with the intention that subsequent readers or listeners would take it as historical, then the situation is the same as in the previous paragraph.

That assumes that it's always the goal of an author to tell the average reader the truth. As early as the 12th when Maimonides writes his Guide there's the idea that the Torah is purposefully written in a way that the average reader doesn't get it's secrets. Only wise people are supposed to understand it. If a story successfully throws off a reader that isn't wise it might have done it's job.