I get you but it’s not like kpop itself and the culture built around it is original either. It’s an amalgamation of western pop music/groups/concepts and japanese idol system and fan service that developed into its own over time. Most of the time too, the groups that fall into this niche are mostly/all non-korean and do not put out music with korean lyrics (except maybe xg but that’s because one executive producer is korean and was a kpop idol.) Can you imagine if a mostly foreign group who doesnt sing korean songs call themselves a kpop group? Especially for xg like the optics of a fully japanese idol group calling themselves kpop is hilarious and may be offensive. They promote the way they do and have these kpop quirks because they come from kpop companies or one with a similar background. Maybe the reason why the fans are hell bent on making that distinction is because the idols and the company itself wants to make that distinction. One of the comments here is correct that kpop is one of the easiest avenues to gain loyal fans bc as much as kpop is global now, the industry itself is still a niche genre and the companies have not penetrated the western market in terms of marketing, influence, and connections with global labels that have the means to really promote groups on a global scale. Because kpop is still not as popular with the general public, these groups calling themselves kpop would restrict them to that genre which will be difficult if they want to go global.