Also Mormons practiced polygyny.
The Book of Mormon allegedly contain's Smith's translation of words written by Mormon. The New Testament allegedly contains words spoken by Jesus. Latter Day Saints hold that Smith's chief role was that of translator.
And, no, I'm not wrong. Jesus, even if we take every word of the New Testament as fact, did not set out to start a new religion. He was a Jew who preached that the end times would come within a generation. Why the heck would he be starting a new religion if he believed the world was going to end any day now? That makes no sense at all. The number of followers he had in his lifetime barely broke into double digits. They weren't trying to convert anyone they were just preparing for the end times. The religion of Christianity didn't start until Paul started preaching to and converting the gentiles. It's a perfect analogy.