I found some interesting information that could explain the "why" blacks were not able to hold the Priesthood, even though Brigham Young denied this is the reason:
From what I have read and seen it is either this was doctrinal or simply introduced because men at the time were not acting by inspiration but tradition. It was common then to think of Africans and dark races as less than white. The interesting thing is Jews are not white but they saw the white Romans as less than them. Honestly, I think the Church has a big mistake on their shoulder and they would like it to go away, but it can't because its a big part of their history. John Taylor said that Blacks were representatives of Satan on earth. Any of you that are reading this a Black person?
I notice that a lot of people online mention the fact that only those of African heritage were under the priesthood ban however, we need to keep in remembrance that in 1958 is when Melanesian "Blacks" were given the Priesthood because David O. McKay defined them as from a different linage and not under the priesthood ban. Before that, they were under the same ban.
Source 6
I watched Part 1 of the DVD produced by Darius Gray called "Blacks in the Scriptures" and the first part deal with the interpretation that the word "black" anywhere in the scriptures refer to skin color but as a synonym of sin or evil.
I believe this is the only quote I came across from a Prophet stating the possibility of the ban being an error, the same Prophet who lifted the ban.
In "The Teachings of Spencer W. Kimball" (6/15/63) he said:
When I first came across Blacks not having the priesthood I 'accepted' or maybe brushed it off as being based on the same Old Testament racialism / tribalism but looking to it more it seemed to be more about racial prejudices at the time. Now I see it as natural given the scenario of the US at the time, but among Prophets and Apostles who should know better or even be informed by the Lord better? Then again if you are thought that the Black race is the representative of Satan on earth from the same people that are supposed to guide you to salvation how can you think otherwise - that is... If you are White.