In Jacob 2:24 it says "David and Solomon truly had many wives and concubines, which thing was abominable before me" the book Joseph Smith wrote says that having multiple wives is an abomination. But it wasn't more than 10 years before Joseph apparently forgot this and started fooling around. D&C 132 is all about polygamy and it says in the chapter heading that it was recorded in 1843 but likely known to some degree by 1831. It's interesting that a god who doesn't change thought polygamy was an abomination when talking to the Nephites but is ok with it 1800 years later. Now to be fair Jacob said polygamy is only ok if building large faithful families and D&C 132 says it's only ok if the first wife approves of it. So let's take a look at just a couple of Joseph's wives and whether or not the rules were followed.
So, let's go back in time to 1831 when the church assumes Joseph must have known some of the details surrounding polygamy. In 1831 Joseph and Emma had a girl working in their house named Fanny Alger [1]. Joseph was between 28 and 32 and Fanny was between 16 and 20. Emma claims she saw Fanny and Joseph in the barn together [2] and Oliver Cowdery called it a "dirty, nasty, affair" and even brought Joseph to the church high council on charges of Adultery. Joseph never denied the relationship but also never called it adultery. Emma didn't know about it and Joseph never had kids with Fanny, so whatever it was, it wasn't in line with the laws outlined in D&C 132.
In 1842 Joseph was hiding from the law and from his wife. This letter[3] to one of the girls he married, Sarah Ann Whitney, and her parents, gives specific instructions for how she can meet up with him where he's hiding and how to avoid Emma in the process. He also tells the Whitney's to destroy the letter. The fact we have the letter seems to me like evidence the Whitney's didn't implicitly trust Joseph. If nothing was happening in this meeting that a married man would be ashamed of if his wife found out, then why did he go to any trouble to hid the meeting from Emma?
The next point I want to talk about happened in 1843. Polygamy was a bane to the church. Rumors followed the church everywhere and inside the quorum of the 12 it wasn't a secret that Joseph had been married to more than a few women. Outside, accusations were leveled and Joseph in front of groups of people would publicly deny that he had more than one wife [4]. Apologists for the church claim that he wasn't lying because his polygamous wives weren't wives they were sealed to him or living with him [5]. So even if he could in gods eyes have sex with them in the eyes of the United States he couldn't without committing adultery. In the church we believe in keeping the laws of the land, but I suppose in this case it was fine to ignore them since God hadn't yet provided a way to keep his commandments. Amidst all this, Joseph married two more women, this time sisters, Emily and Eliza Partridge. He had a secret wedding where Heber Kimball presided. Not more than a few weeks later Emma agreed to let Joseph marry someone, so he could keep God's commandment. It just so happened that Emily and Eliza also worked in the smith house and Emma was ok with them marrying Joseph. So instead of coming clean about already being married to them, Joseph had another wedding to them but this time let Emma attend [6]. This man lied to his wife. He withheld the truth from her. He married women behind her back and if he was keeping the commandments outlined in the Book of Mormon and the D&C then he was having sexual relations with them. Emily and Eliza were Josephs 20th and 21st wives. Emma was sealed to him a few months after Emily and Eliza were sealed to him. His first legal wife wasn't even sealed to him until he had been sealed to 21 other women [7].
If Joseph was willing to lie to his wife. If he was willing to lie to friends and neighbors about polygamy. If he was willing to sneak around behind Emma's back and if he was basically acting like a cheater, then how can we trust that he didn't also lie about the first vision? There are 4 first vision accounts written by him or dictated by him that have major contradictions in them. How can we trust they were real and not fabricated when they appear to change the way a fish story does with time. They get more fantastic as more time passes. How can we trust the story he tells about the origin and translation of the book of Mormon? All the meetings with angles always happened when he was alone. He was alone when retrieving the plates. He hid the plates from sight from everyone, including Emma. And even the witnesses of the plates only claim it was a vision, not a physical experience. As an omniscient being God would have known these kinds of things would happen in Joseph's life, if called as the prophet. Even if God allows prophets to make mistakes, wouldn't God vet the prophet a little better and find someone who wouldn't end up looking like an adulterer, liar and con-man? With billions of people on the planet you would think God could find someone who wouldn't abuse power like Joseph Smith did. Joseph's actions look no different from every other cult leader's actions, especially when he started telling his followers he needed to marry their wives and daughters to himself. That's cult tactics 101. Cult leaders never last long before they start having sex with all the women. Why would God call Joseph Smith as a prophet when we can't see any difference between him and a cult leader? It's literally destroying God's ability to save his children, which he says in the scriptures is "his work and his glory" If my work and my glory was to bring to pass the immortality and eternal life of man, I would not go within 500 miles of Joseph Smith to find a leader for my church. And I'm a dumb human. Why would a god do something a human wouldn't?
4 - https://contentdm.lib.byu.edu/digital/collection/NCMP1820-1846/id/9944/rec/1
5 - https://www.fairlatterdaysaints.org/answers/Joseph_Smith/Polygamy/Hiding_the_practice
7 - https://www.churchofjesuschrist.org/study/new-era/2004/10/when-emma-met-joseph