The problem is worse than that, in ways I don't have the time to explain fully right now. The gist of it is that "Linux" is an incredibly marketable, catchy, easy-to-remember name, and "GNU/Linux" when spoken out loud feels like something you have to hack out of the back of your throat. People say "XP" and not "Microsoft Windows XP" for exactly the same reason that people say "Linux" and not "GNU/MIT/KDE/Linux/etc."
A short, sweet, catchy name is going to be more popular than a longer, uglier name, whether or not it is more correct. Period. If RMS actually cared about his beliefs and his goals more than his ego, he not only would drop the "GNU/Linux" requirements, he'd also rename both the FSF and GNU to be more palatable by regular folks.
"Free Software" is an even bigger mistake, on the account that it really is just confusing to people who don't know what the term means. If I use the term "Open Source" around someone who knows jack and shit about software licensing, then the best case scenario is that they'll figure out what it means on their own and the worst case scenario is that they have to ask me what I meant. If I use the term "Free Software" around the same person, the best case scenario is that they assume I mean "software you can get freely" and worst case scenario they assume it is equivalent to "freeware." Open Source isn't confusing, and it even clearly states in relatively unambiguous terms what it means. Free Software is extremely confusing and super ambiguous. The simple fact that there are a metric shitload of proprietary apps that call themselves "free software" (because that is a perfectly valid English label for the software) is proof enough. Nobody is going to go around calling Internet Explorer 9 an Open Source project, but it's already called free software by people who (gasp) downloaded the beta for free. If I have to attach a paragraph of explanation to a term every time I use it -- not just to explain nuances of the vernacular but to make sure it isn't wildly misinterpreted as something totally different -- then the term is disastrously poorly chosen.
This is why I always use the term Open Source, why I always use the word Linux to refer to an entire class of OSes, and why I pronounce GNOME as "gnome" and not "guh-nome" (because the latter just makes you look retarded as that combination of letters already has an established pronunciation).