It resulted in the Republican candidate winning most of the south, which was the ONLY election in the 19th century that the GOP WON SOUTHERN ELECTORAL VOTES.
I'm not sure I'd read too much into this. Greeley's campaign included ending Reconstruction, so that should have contributed to unreconstructed white voters supporting him.
What did more to bring the South to the Republican candidate was that the unreconstructed white vote was split among several candidates. Meanwhile, the freedmen (newly freed slaves) were obviously going to vote Republican as were a fair number of "scalawags" (white Southerners who supported the Union and Reconstruction) - and since the South was still under military occupation, their rights to vote were still being protected in most areas.
I think that tying Republican victories in the South to a civil rights platform in the Democratic party, if that indeed happened, might be too simple a connection.
Oh, God! Pride of Man, broken in the dust again! -- Quicksilver Messenger Service