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.
I don't agree at all, I would even think that you are missing the point by saying "they don't see it that way". Well, they don't see it that way because they are ignorant. I agree with the author: Finding a way to communicate this, to educate the ignorant (politicians and voters both) is in fact the crucial battle right now.
Whether this little technical demonstration does that or not... well, we'll see. But I absolutely can't fault the effort.
Responding to your edit, "We certainly won't win this battle by trying to teach them information theory (good luck! :) )":
I think your goalposts are shifting here. A simple example that is easy to spread and easy to demonstrate sounds at least plausible. It certainly doesn't sound to me like teaching them information theory, it sounds more like a challenge: "How will your laws prevent me doing this?" Perhaps they'll block Twitter too?
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.