Well then if Vigano is afraid to make a statement to everyone, then I believe that would be called sin of omission.
There have been reports here showing that the SSPX has always considered conditional ordinations almost secrets. As far as I know, there has never been an official annoucement of any conditional ordination. The Resistance clergy simply follows this custom.
Vigano has never said that he considers his Novus Ordo consecration to be doubtful. This being the case, I don't see how he is obliged to come public with his conditional consecration.