I was being facetious about the puzzle part. Upon signing the Civil Rights Act in 1964, LBJ famously said that the Dems “have lost the South for a generation” – by which he meant the southern racists who had traditionally voted Dem since the Civil War. He didn’t anticipate the trend would continue and grow after 1986, which brings us to your question:
Bernays-style propaganda definitely played a part in cementing that stability. The starting point is to understand that the Civil Rights Act pulled the rock-bottom skin privilege enjoyed by poor and working-poor whites (southern and otherwise) out from under them. LBJ is supposed to have told Bill Moyers in 1968:
“I’ll tell you what’s at the bottom of it. If you can convince the lowest white man he’s better than the best colored man, he won’t notice you’re picking his pocket. Hell, give him somebody to look down on, and he’ll empty his pockets for you.”
So the corporate pickpockets to which he was referring found the perpetuation of racism (including via Bible-thumping evangelical preachers) a powerful means of continuing to ply their trade. You don’t give up a tool like that.
Of course the nature of the distraction had to be refined as overt racism became unacceptable, and in stepped one of the most talented heirs of Bernays, Lee Atwater:
You start out in 1954 by saying, “N-gger, n-gger, n-gger.” By 1968 you can’t say “n-gger” — that hurts you. Backfires. So you say stuff like forced busing, states’ rights and all that stuff. You’re getting so abstract now [that] you’re talking about cutting taxes, and all these things you’re talking about are totally economic things and a byproduct of them is [that] blacks get hurt worse than whites. And subconsciously maybe that is part of it. I’m not saying that. But I’m saying that if it is getting that abstract, and that coded, that we are doing away with the racial problem one way or the other. You follow me — because obviously sitting around saying, “We want to cut this,” is much more abstract than even the busing thing, and a hell of a lot more abstract than “N-gger, n-gger.”
Quoted in full because this statement is absolutely critical to understanding what happened in the 1980s. The abstract language happened to dovetail very nicely with rising Reaganite and Libertarian rhetoric about small government, states’ rights, deregulation, removing or weakening welfare, etc. Thus did racism become deeply intertwined with American movement conservatism’s “free” market advocacy, and remains so to this day.
[ETA: to be clear, this does not mean that all Libertarians or Republicans or conservatives are racist.]