I think the combination of the following two things can explain it:
(1) There is unfortunately not much high-quality journalism going on at all nowadays, about any subject. The few journalists who are in a position to do good work need to write about "big" topics.
(2) The topic "GNU/Linux" is unfortunately not big enough, most people (including journalists themselves) don't understand what GNU/Linux is, or what software freedom means.
I hope both of the above will change. 🙂