After living in both a conservative state and a liberal coastal area for years, I've realized that every radically different culture probably looks like brainwashing to other radically different cultures. What we might be seeing is what happens when those cultures compete for the same space.

Much like living organisms, both cultures/memeplexes produce their versions of antibodies and immunities.

Both living memeplexes have developed a sense of "self" vs "defective self"/"harmful other" vs "harmless other", just like an immune system. Both "believe" themselves to be the "true" organism, and that the other is defective. Both have diverged enough that mutual symbiosis is no longer working. Both claim the same space as their own.

Both have failed to process the metaphorical signaling molecules of the other. Driven by their respective fitness functions, both are evolving and diverging.

Ultimately, the two organisms will have to relearn how to communicate and merge back into a symbiotic whole, establish a clear boundary between the two, or failing those, each will continue to seek to destroy the other until perhaps nothing is left of either.