If it's someone else's project, they have full authority to decide what is and isn't an issue. With large enough projects, you're going to have enough bad actors, people who don't read error messages, and just downright crazy people. Throw in people using AI for dubious purposes like CVE inflation, and it's even worse.
As far as I'm aware, most large open GitHub projects use tags for that kind of classification. Would you consider that too clunky?
Absolutely. It's a patch that can achieve a similar result, but it's a patch indeed. A major features of every ticketing system, if not "the" major feature, is the ticket flow. Which should be opinionated. Customizable with the owner's opinion, but opinionated nonetheless. Using labels to cover missing areas in that flow is a clunky patch, in my book.