The freedom to vote was a giant leap forward for the African American population, during reconstruction. Before that, they were never free. They still had to let others choose who were going to enforce laws, and regulations. Andrew Johnson, vetoed the civil rights, but the radicals soon fought for these civil rights of race, and enforced the 15th Amendment.
Since this was written into the bill in 1870, there was definable changes to come. Now that a good chunk of the population had a say in what was being created in the government, a shift of power was taken away from the “pro-slavery” population. On the other hand, this created underground societies, like the Klu Klux Klan, who terrorized African Americans. Plus with the depression of the north, the economic status became center stage, and civil rights went back into the shadows.
All and all though, I believe this movement, brought a slow wrecking ball to all prejudices in illegal injustices. Not to say that today, we should be where we should be on racial or sexual prejudices. The tool of education for class structure is a whole other topic.