interesting question. the phrase appears in the Q drops, and is used by DJT.

Both white hats and black hats have been fighting an optics war. Part of that is choosing people to play roles. IMO central casting refers to the people who choose those actors.

Some of us believe that even our so-called enemies have been controlled or subdued by white hats, and that we are truly watching a movie. If that's true, then there is no active 'black hat' central casting, and it's all just a show put on by the white hats.

then there are doomers, who think that even our allies have been cast to play that role by the bad guys. oh well. the less said about doomers the better.

in any case, there's likely some 'controlled opposition' going on, whether it's good guys acting as bad guys, or vice versa.

It's interesting to note that some political figures, like J. Trudeau and Zelensky, were literally actors before getting into politics.

TL;DR central casting is in charge of casting 'the movie'.