Oldiesfreak, here's the truth in a nutshell:
Democratic Solid South-LBJ does the Civil rights thing-AUH20 wins Deep South-Nixon appeals to the racists in the Democratic party-Racist democrats vote for him-Nixon resigns-Ford and Carter are not racist-Ronald Reagan elected-Black people hate Ronald Reagan-Racists mostly join GOP except for hacks and party loyalits.
It's not so much that Nixon appealed to the racists in the Democratic party as that Humphrey and McGovern did not. In terms of their public rhetoric when it came to either support for civil rights or supposed racial code words, Nixon and Ford weren't that different.