You showed a list of 13 reps and senators that switched from Democrat to Republican but only 1 voted against the civil rights act. You provided no evidence as to why they switched or that they are racists. The rest of the racists democrats (over 60) that voted against civil rights act stayed democrats their whole life.
The grand wizard Robert Byrd represented democrats until his death in 2010. If a devout leader of the Klan is comfortable as a democrat his whole life the racists democrat ideology never left.