The reason people find the DK effect persuasive is that everyone has run into this many times in their own lives. Like with an idiot boss who thinks he knows your job better than you do, or an article by someone that gets things completely wrong about a topic that you yourself know very well, through personal experience or extensive study. And we have all been dismayed about the impact such people can have, like through their decisions or influencing each other.

If the research can't demonstrate the DK effect, then the research is bad, like poorly designed.

Maybe the problem is that DK isn't about individuals, but about topics? I.e. perhaps everyone exhibits the phenomenon about topics they are most ignorant about.

(and I am ignorant about DK, so...)