This is an aside, but why did the author prepend Emacs with GNU every time?

From my understanding, GNU Emacs is a specific flavor of Emacs (which is a general class of editor). From wikipedia, it's the most common flavor of Emacs. Is it not generally understood that Emacs implies GNU Emacs? Would it not be sufficient to introduce the article with, "... Emacs -- specifically, GNU Emacs -- ..." and then carry on with Emacs elsewhere?

It seems needless, or even pedantic, but maybe I'm missing something?