The Book of Mormon as Inspired Fiction?

Some Latter-day Saints insist that the Book of Mormon can be inspired fiction and still be scripture.  According to this view, God “revealed” a fictional tale of the Nephites to Joseph Smith in order to (somehow) inspire people to believe in Christ, accept Joseph Smith as a prophet, and live better lives.  From one perspective this may make some sense; the the parables of Jesus are obviously fiction, yet are scripture.  More to the point, the allegory of the Olive Tree in Jacob 5 is itself fiction, yet Mormons believe it to be scripture.

However, I believe this fictional Book of Mormon approach is logically untenable for at least three main reasons.

1- Why would God inspire Joseph to lie to the Saints–implying in all sorts of ways that the Book of Mormon is authentic history–in order to inspire confidence?  This seems remarkably counterproductive.  Why couldn’t God have simply said, “behold the parable of the Nephites” like he does in the Doctrine and Covenants 101:43?  Or why couldn’t God simply have revealed some authentic lost teachings of Jesus?  Why wouldn’t God try to reveal his eternal truths by talking about real ancient prophets and prophesies rather than fictional ones?  There are a lot of true authentically historical things God could reveal; why not do that instead of revealing a fictional Book of Mormon?

2- The stated purpose of the Book of Mormon is “the convincing of the Jew and Gentile that Jesus is the Christ, the Eternal God, manifesting himself unto all nations.”  If the Book of Mormon is fiction, how can it possibly accomplish this task?  Why is the Book of Mormon any more efficacious in this regard than, say, the late nineteenth century novel Ben Hur?  How does a fictional book about Jesus show that he is the Christ, any more than Superman comic books demonstrate that Superman is real?  How does the fact that Jesus didn’t visit the New World demonstrate that he “manifests himself unto all nations”?

3- The most serious problem, however, are the implications of this theory relating to Joseph Smith’s prophetic claims.  If the Book of Mormon is fiction, then there was no Moroni and there were no Golden Plates.  So, when Joseph Smith claimed he saw the angel Moroni, what was really going on?  Why did Joseph Smith hide non-existent plates in his fireplace?  Why did he cover them with a cloth?  Why did he copy characters from non-existent plates?  Why did he try to show them to eleven other people?  (Indeed, what did he show them?)  What was he really thinking when he made these claims?  If there were no Nephites, then Joseph’s entire foundational story is ontologically false.  Which means he was either lying (he knew there were no plates, but told his followers he had them), or he was delusional (there were no plates, but he was hallucinating that there were).  Either way, the only intellectually honest and coherent conclusion is that Joseph Smith was not an authentic prophet.  The only remaining choices are liar or lunatic.  I simply can’t understand people who say none of this matters.