It strikes me how far gone I am when I can watch, and much enjoy, both the Harry Potter films and The Jewel in the Crown, and see through the foreground moralism to take away a message pretty well opposite from what the author's conscious intention seems to be. To the extent that a story has archetypal power, it must also lie beyond the control of an individual ego. As with any work of art, it does take on a life of its own.
One of things I learned in my years of hermeneutics, philosophical and theological, is that an author, known or unknown, cannot wholly control the meaning of his text, or in Rowling's case, hers. For both Brits, JKR and Scott, their gift as storytellers eventually outruns the constricted bounds of their moral egos. As with constitutional or Biblical interpretation, you can investigate the stated or learned intentions of the author, but in the end it's the text itself. Not only its content, but its literary form, which shapes the content. Not original intention of the authors but original meaning of the text. And the capacities of the readers, of course. Interpretation is always dialogical.
With Rowling, any cheap racial roman a clef that could be drawn from the purebloods vs mixed bloods theme is overwritten massively by the very structures of the world required to hold it. With Scott, if you combine an archetypal eye with a larger knowledge of history, the character one reviewer has described as "the most finely drawn villain in English literature" is revealed as a complex and even ambiguous villain. And subsidiary to the Eve/Pandora characters whose combination of self-righteous curiosity and boundary-breaking set the whole tragedy in motion.
In Ex Cathedra's dialogue with these stories, which fascinate him so much that he has viewed them many times, his allergy to moralism --especially certain kinds of Foolish Leukophore moralism-- reveals, IHHO, a back story at least in tension with, if not wholly at odds with, the high-mindednesss of the authors. Who, in the end, thank God, are far better storytellers than preachers.