Without this irrationality the sedevacantists have no reason to reject Vatican Council II and go into sedevacantism.

From the blog The Eponymous Flower : True or False Pope Part I: John Salza

1. Baptism of desire is NOT an "exception".
   Lionel: The Letter of the Holy Office to the Archbshop of Boston(1949) considers it an exception. This is accepted by John Salza and the SSPX.
   I reject the second part of the Letter(1949) since hypothetical cases could not be an exception to the traditional Feeneyite interpretation of the dogma extra ecclesiam nulla salus.__________________________
   
   If a person makes an act of perfect contrition they are restored to the state of sanctifying grace before they go to Confession, which they must receive at the first opportunity.
   Lionel: Yes.
   However this has nothing to do with the dogma EENS unless you consider it an explicit case and an exception to EENS._____________________
   
   In the same manner, Baptism of desire gives a person who has reached the age of reason the grace of justification before they receive Baptism (again, which must be received at the first opportunity).
   Lionel: O.K but this is a hypothetical case. You personally do not know any one as such. So it is not relevant to EENS.
   For John Salza the baptism of desire is relevant to EENs. This was the concept with which he wrote this book.
   Even for the sedevantists the baptism of desire is relevant and an exception to EENS.So Vatican Council II emerges as a break with EENS and the rest of Tradition.__________________________
   
   Btw, have you actually READ True or False Pope by Salza and Siscoe? If not, then I strongly suggest that you do so before you criticize them.
   Lionel: I strongly suggest Salza and Ciscoe clarify this issue even though it would put them at odds with the SSPX.
   Even before John Salza wrote this book I was in communication with him via e-mails. He ignored it all.
   I am not going to read this book even if I had it before me, it is based on a irrational premise and conclusion. Without this irrationality the sedevacantists have no reason to reject Vatican Council II and go into sedevacantism.
   Who is going to tell them this? Not Salza and Ciscoe.-Lionel Andrades

 

The Catechism of Trent only mentions 'the desirethereof'.It does not state that it is objectively known, and so is an exception to EENs. This was the mistake made by Rome and Boston in 1949.

http://eucharistandmission.blogspot.it/2016/06/the-catechism-of-trent-only-mentions.html