Well to begin with, believing that the story is literally true doesn’t mean the purpose of it isn’t still a theological point, for one thing. You’re comparing apples and oranges.
More basically, you are laboring under a misconception: the hermeneutical principles taught in the catechism (as in the OP; I’m sure there’s more) are exactly the same ones that are taught among fundamentalists. I went to two findie bible colleges, and nobody – not Jerry Falwell, not Bob Jones – thinks that you ignore culture and genre in interpreting scripture; it’s literally one of the first things they teach you.
The sort of absurd literalism that many people here ascribe to fundamentalists would be laughed out of the room at the most fundamentalist Bible College in the world.