Likely from an annual awards anthology or collection. Cold War theme. Russian/Chinese(?) state actor develops 100s of channels of TV content tailored to every type of individual in US to influence behavior. This was back when there were only 3 network stations and before cable was a thing so 500 stations was really "scifi".
The story takes the form of a non-fiction article by Clarke in which he warns the United States that the People's Republic of China is planning to, using a Russian rocket, launch a communications satellite in geostationary orbit to broadcast directly to Americans. The satellite will offer an uncensorable mix of heterosexual and homosexual pornography (using the Kinsey Report as market research), gore (such as details of bullfights and photographic evidence from the Nuremberg trials), and communist propaganda. The American ex-ad man and Communist sympathizer that reveals the plan to Clarke thanks his influential 1945 article on satellite transmission for giving China the idea, and boasts that "History is on our side. We'll be using America's own decadence as a weapon against her, and it's a weapon for which there's no defence".