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.
All of this is possible on GitHub issues and is in fact done by many projects, by this metric I dont see how GitHub Issues is any different than say, JIRA. In both cases, as you mentioned, someone needs to triage those issues, which would, of course, be the developers as well. Nothing gained, nothing lost.