I would like to clarify that I'm not necessarily trying to undermine the importance GNU as a whole. I'm just trying to undermine the needlessly pretentious way people try to force the name "GNU/Linux".
I also realize you are not looking to cause any argument—I am not either—but I would like to provide some thinking points.
I agree with you. The same of what I said about Linux may be said about GNU. In face, one could argue we could have them as separate groups. Linux distros, then GNU distros, rather than categorizing them all as one.
This however, poses a problem for distros that actually use both. Is it a Linux distro? Is it a GNU distro? According to our aforementioned theoretical nomenclature, it can't be both—that would ruin the simplicity of it.
I don't think there's a perfect solution, but as I said before, I feel that the name "GNU/Linux" is pretentious and forced, whereas the name "Linux" is not only easier to say, but is far more recognizable.
In the case of the average consumer—that is, in this context, someone who is not tech-savvy—you'll usually be a Windows user. If they've heard of any other operating systems, those are almost always "macOS" and "Linux".
Does this individual know what either macOS or Linux are? Probably not. But that triad of operating systems is what they know. They're unlikely to have ever heard of GNU, and would only be even more confused to hear "GNU/Linux".
Obviously my example is a generalization and doesn't apply to everyone, but I feel it is still considerably relevant. If for no other reason at all, Linux is Linux because that is what the majority of computer users know it as.