i was unaware that there was a free software definition of fork. for me fork is a technical term that is used to indicate that the forked codebase is going to be developed with a different goal than the original. which license the code has, and what the limitations of that license are, is not relevant for it to be a fork. i can make a fork of a closed source application if i have the code and the legal right to it (which i might have because i paid the owner for that right)
FUTO is not xerox. and i disagree that xerox is responsible for allowing free software to be developed. furthermore, the right to commercial exploitation is not what drove the idea of free software. commercial exploitation was necessary because otherwise selling tapes and other media with free software on them would not have been possible. today where distribution of software can be done pretty much without any cost at all, this right is no longer needed in just to be able to fork and distribute an application.
it is only needed if i want to be able to commercially exploit the changes i make to the application. this is where free software and these new source available licenses diverge. and this divergence is the entire point of these new licenses.
also historically there used to be an active community of the development of non-commercial software. many MUDs for example had a non-commercial license and each one of them was forked many times over.