"The Commons" and "the public domain" might be legitimate concepts with deep and relevant histories, but they're too arcane to most of us. Eric Raymond has told me more than once that the Commons Thing kinda rubs him the wrong way. Communist and Commonist are just a little too close for comfort. Too social. Not private enough.
Or as Lessig sums it up (emphasis is mine):
On such a simple scale, it was clear how the majority of the Court would vote. Not because they are conservative, but because they are Americans. We have a (generally sensible) pro-property bias in this culture that makes it extremely hard for people to think critically about the most complicated form of property out there -- what most call "intellectual property." To question property of any form makes you a communist.
When I wrote about Creative Commons I pointed to this idea that we miss the equivalent of environmentalism for encompassing the concepts of commons and public domain. For strictly ethymologic concerns I had one word in mind... communism. Too bad the word has such a heavy history, we need to be more creative.