Well, the white ones of us, at least. The black ones stayed neutral, and were punished by being incarnated as blacks. (Mormons really believed that, at least before it became politically delicate to do so).
I don’t recall that doctrine ever being canonized. That seems to be a big red herring to me. Blacks have always attended with everyone else. We are a geographic church similar to Catholics. You attend where you live, you don’t go shopping for wards. Even today, in the south there are Black protestant churches. We have never had anything like that. Did you know that Israelites never gave priesthood to anyone but Levites? We have Black bishops, stake presidents in white areas of the church. I don’t hear the attacks on Protestant divisions over race? A big reason we were tossed out of Missouri is because we were abolutionists.