Does true freedom include being bound to a duty to protect that freedom?
With GPL, it works within the existing legal system to ensure that you have full freedom with GPL software as long as you continue to give such freedom to those who use your own versions of GPL.
It reminds me of the issue with a democracy. Does a true democracy allow the voters to replace the democracy with another form of government (say a theocracy) or does a true democracy uphold that the one choice they cannot make is to remove democracy (individually they can stop voting, but they cannot take the vote away from anyone else).
Or take the question of a free market. Given a free market, no man is bound as a slave by default. But does a fully free market allow for a man to sell himself into slavery (and to what degree, as taking on debt might be considered a really light form of indentured servitude, college debt which cannot be discharged could be considered a stronger form, and child support where one can be sentenced to jail could be considered full indentured servitude)?
All of these seem to share a core underlying question, perhaps even an underlying paradox. I'm still not sure what it is, though it does remind me a bit of Russel's paradox in an absolutely rigorless way.