re: Which religion will stand its ground against the gay agenda? [W:743]
Is it a fact at one point in time Mormons viewed black people as a subspecies ala doctrine or not?
Not really.
It is true that starting at some time that cannot clearly be nailed down, and ending with a revelation given to the Prophet Spencer Kimball in 1978, Negroes were not allowed to hold the Priesthood or to participate in the Temple ceremonies.
As I said, it's difficult to nail down when this prohibition began, or why. Joseph Smith held some views on race that, in his day, were considered rather extreme and unusual. He considered Negros to be fundamentally equal to other races, and wrote that he believed that the only thing preventing them from achieving everything that Caucasians achieved was they way that they were being treated. It would be more than a century before such an opinion would come to be widely-accepted among Americans in general.
Brigham Young, of course, held views on the subject that were very much in line with what most Americans thought. There aren't any records that clearly indicate when the Priesthood was withdrawn from Negros, but it was during Young's time. There are some passages in scripture which can be easily taken to suggest that Negros are descendants of Noah's grandson, Caanan, whom Noah cursed because of Ham's offense against Noah; and that part of that curse was that all of Caanan's posterity were to be denied the Priesthood. It's also possible that those bits of scripture didn't mean that at all.
There never was any solidly-established doctrine that clearly said anything at all about the Negroid race; only what I would say were attempts to fit some existing scripture to the prevailing racial prejudices of the day.
It is notable that even during the time in which the Priesthood was withheld from Negros, we were one few very, very few “white” churches that would accept them as members at all.
Whether it was really God's will that this should happen, or merely an unavoidable artifact of the racism that was predominant in that time*, once that policy was put into place, it wasn't going to be reversed without God revealing through his prophet that it should be so. That revelation occurred in 1978, and is canonized in our scriptures as
Offficial Declaration 2 in the Doctrine and Covenants.
* My own personal opinion and speculation† is this: It wasn't necessarily God's will that Negros should have been excluded from the Priesthood, nor made to take a lesser place in the church; but the racism that was in place at the time was such that too large a portion of the white population simply would not have accepted a church that treated Negros as equal. God could have told Brigham Young right away that such a policy was incorrect, and that the Church should treat blacks as equal to whites; and given such a revelation, church policy would have been enacted accordingly. But this would have alienated more potential white members, than it would have gained us black members, at a time, when the Church really needed to be growing in numbers just to be able to sustain itself; and would have resulted in excessive discord within the Church as a result of white members who simply could not accept blacks as their equals. The secular culture within and without the Church had some much-needed growing up to do before it was ready to accept such racial equality.
† Just to be clear, this is my own speculation and belief; it does not necessarily represent any position taken by the Church itself; and it is subject to change depending on any further information or guidance I may receive in the future.