[dredmorbius]

Flipside: copyright is a human construct. So is the GPL and concept of copyleft. It is possible to eliminate one thing (say, overbearing copyright) and protect another. Rather than creating a class of works under license which cannot be constrained, it might be possible to create a set of works under law which may be designated with equivalent protections.

Or find other means to the same ends as the GPL: protecting the three freedoms laid out by RMS.