Ronald K. Esplin states his view that Brigham's views on priesthood ban were rooted in revelation.
Ronald K. Esplin, "Brigham Young and the Priesthood Denial to the Blacks: An Alternate View." BYU Studies 19, no. 3 (1979): 393-402
What he [Brigham] claimed to know by revelation was that the Blacks could not ahve priesthood "except at his [the Lord's] pleasure," which pleasure the Lord would reveal to a prophet long after his own day. Reminiscing about the 1849 statement of President Young to the Twelve, Apostle Lorenzo Snow remembered feeling thankful "that there was no statement that the Negro should never hold the Priesthood and that there would never be a day of redemption for him," and he recognized that "there would always be a man at the head of the Church that would have the keys and who could and would give us the light as he would get the mind of teh Lord." For Brigham Young, as for Lorenzo Snow, it was a matter of considerable importance and teh Lord would not ignore it. But until the Lord again intervened, President Young was certain that the position of the Church, his position, was the only proper one: Blacks were denied the priesthood not by personal whim or historical accident, but by heavenly decree, and until God's purposes had been fulfilled no earthly power could change it.