The “Big Switch” in the 1960s was North vs South, not White vs Black.
No one is saying black people switched any thing. We are talking about how the Democrats were confederate supporters during the civil war and immediately after, and then there was a switch where the Republicans became the party of confederate supporters. Which is why it’s republicans now who are flying the racist and traitorous confederate flags now, and no longer the democrats.
I get your fear, but my optimistic side thinks that trump is special in his ability to self promote to gullible fools. And while the reality denial of trumpism will never completely go away, Republicans will return to some sense of normalcy after he loses his grip.