Chinese censorship isn't Stalinist, or George Orwell's 1984. The censors aren't actively working to eliminate all wrongthink and make an exhaustive catalog of thought criminals. The Chinese government is obsessed (because of the Opium Wars/Taiping Rebellion/etc.) about being humiliated and weak, and so takes on actions that will demonstrate it's power and total sovereignty over Chinese affairs, in accordance with what it's bureaucrats think will make the people perceive a just/fair ruler. It has no interest in waging a futile campaign to totally cleanse the internet, because it would fail at doing so - it would be unbecoming of the powerful to waste time getting mad at reddit posters, who don't really matter. Chinese elites have a much better grasp of their actual power than Americans, and want to avoid creating a phenomenon like Prohibition/the US Drug War where the law is much broader than can ever be enforced and creates tons of lawbreakers among the common people with contempt for government.