Coincidentally, I'm re-reading Lord of the Rings at the moment. Not sure if a work of fiction is the best source of moral lessons, but the whole point of the book is that the Ring of Power would corrupt even the most incorruptible. And somehow, this doesn't surprise me.
Why is a moral lesson in a story a moral lesson? I can invent any moral lesson and put it in a story. That a supposed moral lesson is featured in a work of fiction does not lend credence to it.
So you acknowledge morals can be told through stories. And they are. Like, you know, in the Bible or fables. You just don't believe they have "credence". Which I never asked about. Good debate.
You seem to be extremely confused. Of course moral lessons can be taught through stories. That a moral lesson is taught through story does not make the moral taught true in any sense. Which makes bringing up the One Ring and Tolkien extremely strange.