Stories and codes

Julie Cohen put a comment in my post about Narnia and codes. Actually I knew Julie would feel this way as she was at one point a highly dedicated and passionate teacher of English literature. We differ on the subject in some respects.
While I have no objection to individuals getting more out of a story than the writer intended, I do object to the searching for codes and hidden symbolism as the primary purpose for literary theory. The first purpose of literary theory should be to look at the structure and how the story develops. Without a solid understanding of story theory, it is impossible to say if certain symbolism or meanings are possible or if the reader is merely projecting. In other words, people need to understand and to appreciate the construction as much as they like to love for the puzzles and hidden meanings.
Without STORY, the whole point of reading fiction vanishes.
In some ways, the concepts of plot, pacing, proactive characters and the reasons why they work in one story and not in another are hard to grasp. Why do particular stories resonate with readers at particular times?
So for me as a die hard -- the Story must come first person -- the first test for anything hidden is it possible within the bounds of storytelling craft? Is it possible within world building? Or is it stretching the bounds of credulity? When does literary theory with an emphasis on hidden text and meaning start becoming a discussion of how many angels can dance on a pin head?
Also do stories have to laden with obvious hidden meaning for them to be worthy of study? And can that meaning change depending on the socio-economic context of the reader? Or is it fixed within the social understanding of the author? And if you get a different meaning from the story than the accepted one or the one the author intended, is it necessarily wrong?
Equally, to a certain extent, you need to know when and why certain things were written. For example, in A Question of Impropriety, Diana wears a rose pink gown to the ball. It is highly doubtful that in a historical context, she would have done. I knew that when I put it in there. Why did I do it? To symbolise her movement from the virginal pure state? Actually, it is there because my then editor said in a call about the revisions that she had found a lovely cover with a rose pink gown and the model looked a bit like her, could I make the colour of the gown rose pink. It wasn't important to the story what the colour of the gown was, so I readily agreed.
Anyway, for me, it is always Story, story, story and really it is what commercial ficiton is all about -- in whatever age it is written. Story is what helps literature stand the test of time. That new generations find elements that speak to them is great but it is Story that underpins, not the codes or hidden meaning.