After reading the question about Brigham Young and blacks, I was reminded of the time he said that no one with even one drop of black blood flowing through his veins would ever hold the priesthood. How can one prophet be so far from another (Pres. Kimball) in inspiration?
Again, we must question the accuracy of the reporting of those days. Remember, in those days they used only the memory of the reporter, not the memory of a computer, and only written copy made with ink and a quill pen, not with a word processor. It’s hard for the present world to imagine what communications were like almost 200 years ago. Brigham Young is also reported to have said, “I wish that they would write down what it was that I said.”
In addition, it may be well to carefully check our own sources. My belief is that the reference that you refer to is the following:
“President Young felt it, however, to be his duty to make plain the attitude of the Mormon people in Utah on the subject. In an address to the legislature he said: “The Lord said I will not kill Cain, but I will put a mark upon him, and that mark will be seen upon the face of every negro upon the face of the earth; and it is the decree of God that that mark shall remain upon the seed of Cain until the seed of Abel shall be redeemed, and Cain shall not receive the priesthood, until the time of that redemption. Any man having one drop of the seed of Cain in him cannot receive the priesthood; but the day will come when all that race will be redeemed and possess all the blessings which we now have. I am opposed to the present system of slavery.” (Wilford Woodruff, His Life and Labors, comp. Matthias F. Cowley, p.351)
Apparently you stopped reading after the phrase, “Any man having one drop of the seed of Cain in him cannot receive the priesthood,” or whoever quoted it to you stopped the quotation at that point in order to convey a false impression of what the prophet said. But if you will notice the next phrase, “but the day will come when all that race will be redeemed and possess all the blessings which we now have,” that phrase puts the preceding comment in context, and shows that President Brigham Young was in concert with all the succeeding prophets in their hope and anticipation that the day would come when the blacks would indeed receive the priesthood, and therefore would be equal participants with all the other saints in receiving all the blessings that the Lord has in store for those that love Him and who keep his commandments.