King began to realize that the average white guy and blacks were both victims of the policies determined by the super wealthy. How the wealthy convinced half the voters that poor people are robbing them and the rich are on their side is a mystery.
I think some well-thought-out theories do a pretty good job of at least beginning to dispel the mystery.
Wealthy individuals and corporations and other actors shape political narratives and manipulate the support of working class voters -- against their own economic interests I might add, which is stunning -- through cultural manipulation, media control, and the creation of false narratives that seek to redefine economic struggle.
FoKKKs started the "culture war" to distract poor people. It worked, so the right adopted it like it was the child they always wanted and would always love.
Rich and powerful interests invented the "reverse Robin Hood" narrative. Policies that only support them -- and not the working class itself -- have been rebranded as "job creation" and "pro-growth". Unintelligent or easily manipulated people fall for it every day.
Far right and far left media are both toxic to the body politic, but the far right is really some utterly insane stuff. Many people on the right only listen to it, so the echo chambers intensifies, and the listener becomes more and more ingrained in the cult.
We also can't forget that one of the right's favorite and most effective weapons against the poor and middle classes is psychological manipulation, including gaslighting. The wealthy convince the working class to be angry at "lazy" people, welfare recipients, and immigrants. That way, they go back to their jobs every day completely oblivious to the fact that the corporations that employ them actively suppress their wages and standards of living.
Money runs the US. Money has corrupted almost everyone who has any appreciable power or influence. Billions and billions of dollars have been deployed to trick poor people that the right has their back when the only reason the right can see their back is because they're stabbing a knife into it every single minute of every single day.