I was asked to explain this situation in my questions site (the link being at the top of the page). And having done so, I felt it important enough to be presented here. Even though what I am about to say was given to me by inspiration, I can demonstrate it to be true, from scripture and church doctrine.
Having stated that, I must declare that the things I say are purely as a church member, not an authority of the church. And I have never heard or read a general authority of the church, living or past, make these comments. Or any other member. So I must declare them as only those things of which I have been informed by the Holy Ghost as one person. Not established church doctrine.
My purpose in placing this here was primarily in consideration of any negro who may be searching for understanding. Secondly for any other seeker of truth.
In the pre-existence Satan presented a plan that was impossible, but appealed to many. One third of all spirits present, in fact. Of the other two thirds many were not certain who to go with. They had concerns. Being loving, Heavenly Father made a deal with them that if they went down he would make sure that they couldn't go to outer darkness - which, apparently councerned them. To go there requires the priesthood. So he promised them that a mark would be put on them that no one would put them in the position they feared. In his love God placed a dark skin upon them to distinguish them from those wishing the priesthood. He made sure that these spirits were born to negro parents. Of more recent years there seems to have been reached a point where these have all come down already, or aren't in a position to receive that which concerned them. Consequently the priesthood has also been given to negros since that time.