In order to figure out which servant was stealing from him, Napier instructed each to go in the shed and pet a magic rooster that he claimed could reveal to him who the thief was. In reality, Napier covered the rooster in soot. Thus he could identify the culprit-- it was the only servant who exited the shed without soot on their hands.
Here, you correctly applied one sense of the Gell-Mann amnesia effect-- a novelist's speculation about experts' inability/refusal to generalize their criticism of a news item within their field to the entire newspaper that contains it. In practice, however, "Gell-Mann amnesia effect" is a gambit that giving a proper name to rank speculation will cause the speculation to propagate as if it were an insight gleaned from a robust research project. If you had understood that part you would have used the rank speculation only an entry point for a comment that provided greater insight (or at least further rank speculation), rather than an insightful phenomenon unto itself.
Edit: In other words, you've emerged from the shed without anything other than someone's rank speculation masquerading as research. This makes it clear you've fallen for the 2nd-order effect of the term.
Also be wary of: Overton window