Either that or he doesn't want to call any more attention to the Vigano June 9th letter than he has to. Hard to say why he didn't mention him. Could also just be because he intended to write the article in broader terms and did not want it necessarily to be viewed as a point-by-point rebuttal of +Vigano. It really wasn't. It was really just a re-statement of his original position to which +Vigano was responding. So, for example, +Vigano disagreed with his example of the traditio instrumentorum as precedent for reforming a Council. Here +Schneider merely re-states that without refuting +Vigano's objection to it.
Viganò starts his June 9th letter with "I read with great interest the essay of His Excellency Athanasius Schneider ..." and he compliments "His Excellency’s study summarizes, with the clarity that distinguishes the words of those who speak according to Christ ... " and Viganò praises Schneider "The merit of His Excellency’s essay ... ".
Let's assume that Scheider is 100% sure that the letter is indeed of Viganò and not of some ViganQ-phantom. Why doesn't he mention the name of Viganò? Why does Schneider not answer to "we inevitably fall under the condemnation of the Decree Lamentabili"? Why does Schneider simply repeat his stance without touching the objection of Viganò? What is Schneider's letter good for, if he acts as if Viganò hadn't said anything? Schneider is acting as if Viganò didn't exist at all.
It's clear: The proposal of Viganò is beyond any allowed position. It can't even be mentioned or responded to. Guys like Skojec are thick enough to reveal that they agree, but Schneider cannot. Schneider knows that admitting a "parallel church" and admitting "we all knew that the Council would be more or less a revolution" (Viganò) would reveal that he's been a revolutionary all the time, too. The only thing uncomprehensible is, how Viganò can on the one hand admit to having served the Antichrist for 50 years, and on the other hand not figure that that implies that he lost all credibility and should retire in hiding.
Assuming that it is Viganò.