"They want the Government to create a Prohibition so they can have a Monopoly on content"
That said, I do think 'Prohibition' is an accurate description. SOPA may well be the first step in a 'War on Piracy' that does have strong parallels with '20s prohibition and the drug war. SOPA is a futile attempt to stop normal human behavior - sharing of content. It won't work. The fact that it won't work could lead to even more draconian blocking measures, creating a self-reinforcing loop of ever-escalating restrictions and punishments. 'Prohibition' conveys that futility and extremeness pretty well for a single term.