Racist SOUTHERNERS started this.
Racist SOUTHERNERS started the KKK.
Racist SOUTHERNERS used the party they belonged to push their racist agenda.
Racist SOUTHERNERS switched parties between 1948 and the 1980s when said party started giving in to pressure from NORTHERN members of said party to lean the opposite way.
Racist SOUTHERNERS who had started this continue to pressure for it via the party they switched to.
THAT'S why it was, is, and forever shall be a Racist SOUTHERN thang.