Creative commons license problem?

There's an interesting essay on Kuro5hin suggesting there may be a problem in practice with creative commons non commercial licences.

One particular licensing option, however, is a growing problem for the free content community. It is the allow non-commercial use only (-NC) option. The "non-commercial use only" variants of the Creative Commons licenses are non-free, and in some ways worse than traditional copyright law -- because it can be harder to move away from them once people have made the choice.