This isn't about the triviality of implementing rc4, it's about the absurdity of banning information in a general sense.

Information can be copied at zero cost, transmitted instantly over vast distances, and stored permanently and undetectably in the human brain. Information spreads like a virus in a very literal sense - you overhear a scrap of plot and suddenly a whole film is spoiled. Trying to ban information is a futile as trying to arrest people for catching influenza. This isn't like banning campfires, or even like banning firemaking implements, it's like banning the very idea of fire.