Forcing people to share's one's version of freedom is not...free.This is exactly how I feel. And some people might say, "Well, that's fine. But how can we all co-exist with differing versions of freedom?" And to that I would say, by having the kind of legal system which enables a variety of contracts which convey those different freedoms and stipulations over our creations.
Some bonus cherries with this approach is that people are dynamic. Their values and opinions are in a constant state of flux. Many (most?) people tailor their principles to match circumstances. Under the variety-of-contracts system, people can use different contracts at different times on different projects for different purposes. Like Asay thinks of the GPL, I think a CC-BY-NC-SA licensed product is like a bomb for a (would-be) competitor.
So someone can tactically employ CC-BY-NC-SA and CC-BY-ND simultaneously to create a dual-license business model. Imagine that - more variety among licensing principles and terms makes good business sense.