There's more to it than that. You're essentially repeating the Democrat claim.
I know she's not popular here at FR, but that book will open your eyes about voting patterns, the truth about the "Southern Strategy" and why it somehow didn't work with Carter, Clinton and Obama. In addition she notes that all but one of the segregationist democrats who stayed in the Senate became liberal kooks. These people stayed democrats for the rest of their careers with the exception of Strom Thurmond.
Even George Wallace on his deathbed proclaimed his eternal allegiance to the democratic party.
That's right, the "segregation forever" guy was NOT a republican.
And to tell you how powerful the democratic lock is on black voters, Wallace reliably got quite a lot of votes from blacks. IIRC 30-35%.
That's right black people voted for a segregationist DEMOCRAT.
“There’s more to it than that”
Civil Right’s Act turn south blue. Goldwater carried southern states in 1964 and Nixon’s southern strategy took them in 1968. End of story?
What is missing? What else occurred?