If you think "It's not censorship unless the government does it," I want to change your mind.
It's absolutely true that the First Amendment only prohibits government action to suppress speech based on its content, but the First Amendment is not the last word on censorship.
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Here are some kinds of private speech-suppression that I think most of us can agree are censorship: when the John Birch Society burned mountains of rock records and novels - or when Tipper Gore's PMRC pressured record stores to drop punk, metal and rap albums.
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Or the Comics Code Authority, which signed up all comics publishers and retailers to block comics if they contained anything unfit for small children, which stunted American comics for generations while their European counterparts created entire sophisticated genres.
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Or MPAA ratings, in which a secret group of censors (falsely described as frequently rotated, randomly selected parents - really they're long-serving studio insiders) decides whether movies get NC-17 ratings and thus be blocked from nearly every screen in the country.
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(You can learn more about this from Kirby Dick's unmissable doc, "This Film Is Not Yet Rated," which documents both how the MPAA misleads the public about ratings, and uses them to block LGBTQ