I'm pretty sure you misread the claim. When it says "full desktop experience" it doesn't mean that FreeBSD ships with a full desktop experience that is already

I'm pretty sure you misread the claim. When it says "full desktop experience" it doesn't mean that FreeBSD ships with a full desktop experience that is already enabled and active by default, but rather that it's possible to get a full desktop experience in FreeBSD (which is very much not the default - it boots to a terminal) and explains how to do that. "Full burger experience" might be the title on a recipe for making a burger, or it might be part of an advertisement for a restaurant where the burger is already made for you. In the case of this article, it's the former. People already in the know about FreeBSD are generally not expecting a full desktop environment out of the box, so they won't be confused about the title.