It is fairness in terms of "I will let you use the source code I wrote, but you need to let me use any changes you make to it". It's not about "everyone's freedoms", that's what Free Software and RMS are all about. Linus has always said that his choice to use GPLv2 was about the reciprocity of contributions to the kernel project, not about the freedom crusade of RMS (to the point of calling Free Software people "insane").