Let me know if I'm oversimplifying this, and if so, please explain why:
God said in the Book of Mormon that he'd only command polygamy if he wanted to raise up righteous seed.
Joseph marries Helen.
1) If they have sex, they are fulfilling God's command to raise up righteous seed.
2) If they don't have sex they're not fulfilling the commandment on which polygamy is predicated.
If 1) then Joseph Smith is a morally repugnant person and his God is a sick POS.
or
2) He's breaking the reason for the commandment by not having sex with his child bride.