[alanstorm]

I'm not speaking for Stallman of GNU here, this is pure conjecture based on too many years of following these discussions. The "problem" with public domain software, (and BSD/MIT) style licenses, is people can take that code, make changes, and seal it back up into proprietary binaries where users lose access to the source code. The ideal world that the Richard Stallman character wants is one where if you're using something that was built with code, you have access to that code, and can't be stopped from using that code. Everything that people in the GNU camp do is towards that goal. Their choice to assert a GPL copyright (or copyleft, if you want to get really hippie) is a pragmatic one, because they recognize that the power dynamics of business lead companies to stop sharing most of what they're working on.