The South was a powderkeg, but it's possible the nonviolent protests of the type inspired by Parks and MLK might have been less prominent that the more militant movements. It still might not have worked out the way Krasko wanted in the end (I think the point is that the Alt-Right don't actually have a clear gameplan beyond "keep them frightened") but a LOT more people might have suffered and died. And that could have rolling implications - lots of historical figures might not have had the opportunities they got because of the Civil Rights Movement, even if it was delayed say a few decades.