But how Dunning Kruger are you to put that down? Like chess has a pretty well known rating system that even a moderately interested player would know about. So in the case of chess you can’t even claim that you didn’t know you are not that great.

You can put down you’re decent at Java or C++ or Python and actually be not that great at it because you have nothing to measure against. But in chess there is a rating system. So you ought to know if you are truly remarkable or not. If you think you are remarkable enough to put it down and then suck at it, how ignorant must you be?! And more importantly, that ignorance is not at all tempered by humility.