I would have to be in the same camp with you on this. I think you opinion matches mine on this matter. And it is not to put there "collection" down or anything. But call it what it is...a graphic novel collection.
This pattern, that you are seeing more and more of from your findings could just stem from lack of education. Graphic novels are just a collection of reprinted comic books. They may see the comic book part and just classify it as such without knowing the true diversion. It is also reasonable that they "the poster" seen others calling it a comic book collection and in turn figured they have one as well. So in short. Yes it's a collection, but a graphic novel collection. It would be nice to eductate people on this matter. But bright side is that these stories, collections and art are being a appreciated.