One of the current favorite lies of the rightwing is that the Republicans are and were the party of civil rights and the Democrats are and were the opposite. This is really too stupid to bother to debunk, the political equivalent of flat earth or chemtrails.
Nevertheless, either rightwingers are really stupid or really dishonest, because, as I say, it's one of their favorite memes -- second only, perhaps, to the lie that socialism led to more deaths than any other ideology. (It isn't even in the top 2.)
Gary Legum, the king of snark, has a hilarious (and very well informed) takedown of this meme, and you should file it away for future reference.