Big deal. I already mentioned that Young's concepts had been repudiated by the Church (which is not the same thing as being repudiated by Bruce McConkie, but they have nonetheless).
What does this add to the discussion? That's Elder McConkie's opinion and its as good as any other. I think there may be more to it than that, however. Either way, Young himself taught the orthodox, accepted understating of the relationship between the personages of the Godhead his entire life. The question, it seems to me, is not explaining why or what he was teaching privately to a few friends and associates, but why he continued teaching the orthodox view throughout his life?
The answer may be that he was experimenting with some things he was trying to work out in his own mind and really couldn't make it work and so gave it up.
Oh well. What does this change about the legitimacy of the Church?
It changes nothing about the legitimacy of the church as long it admits it’s based on men trying to “work things out” in their own minds rather than based on revelation that is clear enough to be “binding”.
And, by the way, he wasn’t “teaching Adam-God privately to a few friends and associates”. He, in fact, chastised Saints who would NOT accept this teaching.
He also couldn’t get straight whether or not the practice of polygamy is required for exaltation. Knowing whether or not a certain ordinance is required for exaltation seems kind of “binding”, doesn’t it?
by the way, you had asserted:
Again, there is no "Adam/God" theory. Young never taught one. The somewhat incoherent stuff he left us has, in the form we have it and as it has been interpreted, repudiated by the Church. No other Prophet taught it (which is telling, given the cachet it's been granted, but only outside the Church).
BRM:
Yes, President Young did teach that Adam was the father of our spirits, and all the related things that the cultists ascribe to him.
This puts me in mind of Paul's statement: "There must be also heresies among you, that they which are approved may be made manifest among you." (1 Cor. 11:19) I do not know all of the providences of the Lord, but I do know that he permits false doctrine to be taught in and out of the Church and that such teaching is part of the sifting process of mortality.