Brigham Young said some unfortunate things, as recorded in the Journal of Discourses. You are well aware of that. What matters, however, is that just as Jesus grew from "grace to grace," the Church--through its living prophets--has done the same thing. If you're going to claim that what Brigham Young said circa 178 years ago is still Church doctrine, than--for the sake of consistency--you must claim that the following statements are still scientific doctrine: 1) "Heavier-than-air flying machines are impossible." --Lord Kelvin, President of the Royal Society, 1895. 2) "I think there is a world market for maybe five computers." --Former IBM Chairman Thomas Watson, 1943. 3) "Who the hell wants to hear actors talk." --Harry M. Warner, Co-founder of Warner Brothers, 1906. 4) "There is not the slightest indication that nuclear energy will ever be obtainable. It would mean that the atom would have to be shattered at will." --Albert Einstein, 1932 5) "That the automobile has practically reached the limit of its development is supported by that during the past year no improvements of a radical nature have been introduced." --Scientific American in a 1909 report.
I don't see you dwelling on these scientific statements as you dwell on statements made by BY when the Church was in its infancy.