You seem to be under the delusion that those Democrats were liberal when they were conservative. Racist conservatives if you may. However as I have stated I'm talking about conservatives who seemed to populate both parties.
The Republicans who voted for Civil Rights were from the the Northeast primarily and Northern midwest and West. Many were part of the Rockefeller Republicans who were socially liberal. Once the civil right law was passed and Nixon implemented the Southern Strategy many of those Republicans faded away or were drummed out. Since that time the Republicans have apologized for that strategy but still use all the proper code words so they can attract those racist voters.
News 
Market Data 
Discover 
