The Dunning-Kruger effect is about mis-rating yourself with respect to a known field, such as one's abilities in reasoning, grammar and humor compared to the average distributions of skill in that area (the original areas studied).

This article talks about things completely unrelated, such as misjuding one's own skill at Street Fighter because one is unaware that a hardcore scene in that game even exists. If that scene did not exist, the hypothetical amateur Street Fighter player would be none the wiser--yet he would no longer be "misjudging" himself due to his own "incompetence".

It looks like the author himself is suffering the Dunning-Kruger effect, spouting pop psychology nonsense in an authoritative tone.