It wasn't a switch as in politicians jumping ship from party to party in most cases, but instead a high level policy switch of voters, purging politicians from one party, and gaining new ones on the other as Dixiecrat voters felt betrayed and were welcomed into the Republican party as a new policy shift of that party.
Framing this as the civil rights act being solved and now voters focusing on other issues is ahistorical, and essentially just propaganda.
The "party switch" is ahistorical, and essentially just propaganda.
Republicans, who for years had been fighting to pass civil rights laws, didn't one day suddenly decide to become the party of Jim Crow, KKK, and slavery. That's democrats, who even today (now that the old stuff is unacceptable in public) have low expectations for some races.
Purging politicians from one party would be great. We can start with the Virginia governor who went to a party in blackface, with his fiance in classic KKK garb. We have pictures, matching pictures of him in the same plaid pants, an awkward admission of guilt, and still he remains in office. This is 2020. He is in office.
Next up would be Biden. There is plenty of video of him saying... that word... to rudely refer to black people. Oh wait, he's the party's presumed 2020 candidate for president!
Nothing deep has changed. It's just being smarter about public relations.
Framing this as the civil rights act being solved and now voters focusing on other issues is ahistorical, and essentially just propaganda.
That's what the mean by a party switch.