the GPL is largely untested in court.
No it isn't. It's been tested at the federal level.
Daniel Wallace tried to get the GPL declared invalid through stretching of legal concepts, and was thusly shown how stupid
Wallace v. International Business Machines Corp.
From Wikipedia, the free encyclopedia
Wallace v. International Business Machines Corp. et al., 467 F.3d 1104 (7th Cir. 2006), was a significant case in the development of free software. The case decided, at the Court of Appeals for the Seventh Circuit, that in United States law the GNU General Public License (GPL) did not contravene federal antitrust laws. Daniel Wallace, a United States citizen, sued the Free Software Foundation (FSF) for price fixing. In a later lawsuit, he unsuccessfully sued IBM, Novell, and Red Hat. Wallace claimed that free Linux prevented him from making a profit from selling his own operating system.
And this quote from the decision shows that the courts completely understand the values behind the GPL and copyleft.
From the 7'th Circuit decision of the Wallace vs. IBM appeal:
People may make and distribute derivative works if and only if they come under the same license terms as the original work. Thus the GPL propagates from user to user and revision to revision: neither the original author, nor any creator of a revised or improved version, may charge for the software or allow any successor to charge. Copyright law, usually the basis of limiting reproduction in order to collect a fee, ensures that open-source software remains free: any attempt to sell a derivative work will violate the copyright laws, even if the improver has not accepted the GPL. The Free Software Foundation calls the result âoecopyleft.â
And notice the subsequent utter silence from Darl and the lawyers at SCO, who were jumping up and down about the so-called unconstitutionality of the GPL. Among other things.
The validity of the GPL is now settled law.
but any element of it that is reasonably subject to interpretation can be interpreted any way you like
This is why you aren't a lawyer.
BMO - not a lawyer, but someone who doesn't agree with people who think that lawyers perform magic. They don't.