I'm actually not taking a position, but trying to help provide nuance in a debate that often teems with zealotry, and do so in a reasonable manner to provoke thought rather than vitriol.
My unexamined default inclination would be toward a BSD or MIT style license than a GPL. You may infer what you like about my default leanings in other areas if you like.
I've not given enough thorough thought toward software copyright to have a strong opinion as to the morally right position. This is not to undercut my comment and the observations I made above, but to make clear my standing which is ambivalent. I can certainly understand both sides of the argument and respect the position people speak from for either (to be explicit, the poles of the continuum being public domain on one end, with MIT/BSD licenses leaning far that way and hardcore copyleft on the other with GPL being the canonical example toward that end).
Toward the Friedman quote, that was not an attempt at appeal to authority to discredit the idea of copyleft, but an observation about the type of person (or at least the general tone of argument) who most vocally defends GPL licensing. If anything it was an appeal to authority to please be thoughtful about how to respond to my comment, and more to the point of why I included it, because it popped into my mind while responding.
This is a long-winded non-answer so far.
Really, what I was trying to do was to emphasize that there are costs to a GPL license, and that a reasonable person may think of those costs as such and not as freedoms. If you look at my response to a sibling comment, I'm thinking about this in terms of negative vs positive rights.
Looking at Friedman, I would certainly characterize him as someone who leans toward defining negative rights as freedom/liberty and positive rights as limitations thereupon. I would also characterize myself as leaning that way (so maybe I'm attributing my own views onto him). This is not to imply you are a hypocrite or declare that it is right or in any way argue against a GPL copyright in general, but just an observation.