Right. Just to be clear, "an effect like this" is (comparatively) unreliable tests, not some elusive statistical phenomena as implied by the original article. I'd have no issue if the author had called the article "the DK effect is due to poor skill tests", spent 5 minutes showing that the DK results are consistent not only with their claims but also with unreliable tests (like you did), then went on to show data that indicates that the tests indeed are not reliable enough to draw the conclusions that DK did. Instead the author spends a lot of time digging under the wrong tree and no time at all saying anything about the reliability of the tests.