Although the Lord commanded the adoption—and later the cessation—of plural marriage in the latter days, He did not give exact instructions on how to obey the commandment. [...] When God commands a difficult task, He sometimes sends additional messengers to encourage His people to obey. Consistent with this pattern, Joseph told associates that an angel appeared to him three times between 1834 and 1842 and commanded him to proceed with plural marriage when he hesitated to move forward. During the third and final appearance, the angel came with a drawn sword, threatening Joseph with destruction unless he went forward and obeyed the commandment fully.
Did you catch that? God couldn't be bothered to tell Joseph Smith what he was supposed to do exactly or why, but he was insistent enough that his prophet get with other women that he sent an angelic hit man to lean on him.
"Goddammit, Joe, you faithless fuckface, I'm gonna count the three!"
What kind of loving being would act like that? Why is that God's more than willing to lay out explicit instructions for communicating with him, ship building, tabernacle design, temple building, temple dealings and just about all aspects of our daily lives (including diet), but not for plural marriage and temple sealings?
Wait, what? He did give explicit instructions to Joseph on how to practice polygamy in 1843? Hm...