Mormonism is different, because they present a series of books that they claim are additional material that contradicts all others
If you're not a Christian, why do you give a rat's ass about their "additional material?" All religion is based on text that is supposedly from God's lips to their ears. There is zero difference. You are the liar. That you're OK with Christianity, but you don't believe it, but you're upset with material that contradicts Christianity is complete bull crap.