The first sentence in your dual-n-back article is:
I meta-analyze the >19 studies which measure IQ after an n-back intervention, confirming that there is a net gain of medium effect size.
If you believe that there's a net gain of medium effect size then why do you think we should throw dual n-back under the bus?
You should probably have read part of the second sentence: "active vs passive control groups criticism: found, and it accounts for most of the net effect size".
Jason Mitchell is [edit: has been] the John L. Loeb Associate Professor of the Social Sciences at Harvard. He has won the National Academy of Science's Troland Award as well as the Association for Psychological Science's Janet Taylor Spence Award for Transformative Early Career Contribution.
Here, he argues against the principle of replicability of experiments in science. Apparently, it's disrespectful, and presumptively wrong.
This is why we can't have social science. Not because the subject is not amenable to the scientific method -- it obviously is. People are conducting controlled experiments and other people are attempting to replicate the results. So far, so good. Rather, the problem is that at least one celebrated authority in the field hates that, and would prefer much, much more deference to authority.