That may very well be true. I would say that the Law of Sarah was not the only law that governs polygamy.
I agree the Law of Sarah wasn't the only law to govern polygamy. Section 132 says there's more to explain on the subject, but it was never revealed.
But let's remember the original question: why would Joseph Smith be condemned but Abraham wouldn't.
I don't think marrying your deceased brother's wife falls under the law of Sarah. No mention of getting the current wife's approval.
No, it would fall under the Law of Moses. Neither Abraham nor JS is subject to this
Taking a wife from the spoils of war also doesn't fall under the Law of Sarah.
I'm not familiar with this ever being a commandment anywhere. Maybe you could cite the source on this?
Sure, it would be great if the wife agreed or even offered, I suppose. But that doesn't mean she has to, obviously.
Here's the text giving the law, and conditions upon polygamy is justified, and not adultery:
"And again, as pertaining to the law of the
priesthood—if any man espouse a virgin, and desire to espouse another, and the first give her consent, and if he espouse the second, and they are virgins, and have vowed to no other man, then is he justified;"
1. The woman is a virgin.
2. The first wife must give her consent.
3. The woman is vowed to no other man.
Here is where Abraham was justified and JS wasn't.
The addendum to the law of Sarah is here:
65 Therefore, it shall be lawful in me, if she receive not this law, for him to receive all things whatsoever I, the Lord his God, will give unto him, because she did not believe and administer unto him according to my word; and she then becomes the transgressor; and he is exempt from the law of Sarah, who administered unto Abraham according to the law when I commanded Abraham to take Hagar to wife.
66 And now, as pertaining to this law, verily, verily, I say unto you, I will reveal more unto you, hereafter; therefore, let this suffice for the present...
My understanding of this is it must be commanded by God and according to his word.
This is where we just have to leave it up to the individual and God, that there's really no absolutes. If JS was being deceived then it's on him, but if not, then all those condemned JS stand condemned.
And yet, I also stand form in the belief that when that truth is clearly demonstrated to our minds, we have the right to embrace it. And if it's declared the word of God, which is made pertinent to our salvation, we have the right to receive spiritual confirmation.
I don't believe a spouse should covet their own spouse, of love their spouse over obeying God's command. So I can see where it would be a great trial of faith to the benefit of the individual.
At the same time, I also see where a priesthood holder could abuse his power, and get easily deceived with no check and balance in place.
In the case of Fanny Alger, whether inspired or not, JS made a mistake in how he implemented this practice.
I'm pretty sure that the law of Sarah doesn't apply to a widower seeking a second wife either, do you think?
All I can say is ask, seek, and knock. I've heard stories of spouses communing beyond the veil. I imagine that if I'm faced with that situation, I'll be doing my best to find someone my wife would get along with and imagine she'd approve of. I believe the law is wisdom for our eternal happiness.