I never heard of anything about this, even from my father who was stationed in South Korea in the '80s. I can believe such bullshit exists, and in other places around the world. I'm sure eventually in the USA 'freedom of speech' (something I don't believe in) will be curtailed by the state.
"But here steps in Satan, the eternal rebel, the first free-thinker and emancipator of worlds. He makes man ashamed of his bestial ignorance and obedience; he emancipates him, stamps upon his brow the seal of liberty and humanity, in urging him to disobey and eat of the fruit of knowledge." ~Mikhail Bakunin