You have crossed from facts which you know into speculation about my mental processes, and in fact you are incorrect about the latter. Without any preconceptions about this whatsoever, I read the Ars article and it strongly suggested to me that the claim was that the infection itself had spread over an air gap.
Otherwise, why even lead from this story into the theory of communicating via sound? If indeed the computer was already infected, then it would be no surprise that it could do something like interfere with running a registry editor. The air gap jumping would be entirely irrelevant to the story.
In other words I'm agreeing with you that the Ars article was misleading. But my initial comment was not meant to be critical of Dragos or anybody else. It was an honest, uncharged question about how my reading of the Ars article would be possible, even theoretically. The answer (it sounds like) is that the Ars article misled me about what Dragos was actually claiming.