If you want to be a Mormon, but you don't think that the Book of Mormon is literally true, you could call it "inspired fiction". This means that instead of thinking Joseph Smith made up a bunch of stories that aren't true, God told Joseph Smith to make up a bunch of stories that aren't true. (What's the difference? Well, if God does it, it's all right, you see.)
When I see someone taking this tack, it's like they're saying, "Oh, of course the Emperor has no socks, but the rest of his couture is exquisite!" It's a partial credit situation; points for realising it's not true, but demerits for going along with it anyway. Call me crazy, but it matters to me if my beliefs are true. If it's not true, I don't have time for it.
What about the idea that, although not true, the stories in the Book of Mormon are good moral stories that can help you to live a better life? That's where it all comes down. The Book of Mormon's a terrible guide for moral living! Here's what you'll find:
- Cutting someone's head off because you think God has told you to
- Dark skin as a curse
- Predictably Victorian notions about the chastity of women
- War after tedious war
- Jesus kills entire cities full of people, and brags about it from the sky while the people wail for their dead friends and family
- Unforgivably torpid prose
Are there no other fictional books that people could use as a guide for life? Of course there are, but it doesn't really matter to these people -- I suspect the reason they've mistaken this awful book for a guide is that either they're tied to it by their social group, or maybe they enjoyed reading it and believing in it once, and they can't bear to relinquish it completely. Which is kind of sad. I can understand if someone thinks these stories are a literal true account of the dealings of a cruel god that they have no choice but to obey -- who can say how they'd act in a hostage situation? But imagine not thinking this stuff is true, and digging on it anyway. Somehow I think that's worse.