I am sorry to say, but(and I am not being a sedevacantist, however you spell it) you are being unfair in calling the supporters of the Siri thesis sedevacantists. Sedevacantism is the thory that John XXIII to Roncalli, since they were elected holding diffirent doctrines(that is, heresies), they could not be legitimate Popes because a heretic, since he is excommunicated, cannot become a Pope.
Pope Paul IV, *Cum Ex Apostolatus Officio, 1559 Ex Cathedra: “We enact, determine, decree and define:that if ever at any time it shall appear that the… Roman Pontiff [Pope] prior to his promotion or his elevation as Cardinal or Roman Pontiff, has deviated from the Catholic Faith or fallen into some heresy: the promotion or elevation, even if it shall have been uncontested and by the unanimous assent of all the Cardinals, shall be null, void and worthless.”
The above was done by the Pope speaking as the Pope. And the Pope cannot err in faith and morals. Now sedevacantists hold that Roncalli-Ratzinger were lected, but are nt legitimate Popes. Hence, the chair of Peter is Vacant(sede-chair, vacante-vacant).
But the supporters of the Siri Thesis hold that Siri was elected, accepted the Papacy, but was forced by the freemasonic Cardinals(infiltrators) to let them put Roncalli on the Chair of Peter… or else, they will kill his family and persecute the entire Church if he accepts. **And let nobody say that I am supporting the Siri thesis or that I am a sedevacantist. ** I had a friend whose account was locked for supporting the Siri Thesis, yet, he said it was unfair because he was locked for ‘sedevacantism’. I really mean not to break the rules, excuse me but, I see this as a bit unfair. I ahve just said how the Siri thesis supporters are not sedevacantists.