I don't guess. I believe that our knowledge of his sins in no way qualifies us to declare the pope deprived of his office, or never to have been elected.
I think his is an unfair simplification of the sedes position, "declare" is a loaded word that has no meaning in this context.
My position is the default position, i.e. is he is pope because he was elected according to the law
Ahhh no...
Even according the the "laws" of JPII neither Francis nor Leo would be validly elected.
Case in point,
1) The gerrymandering of the St. Galen Mafia for Francis and his subsequent admission of this fact prior to his death.
and
2) Because Francis stacked the College with more electors than JPII's laws laid down which stipulates that deviations from the law invalidate the election - Francis never bothered to change it - big problem.
Both carry enough doubt that one such as Dr. Mazza, Brother Bunguglo, Beneplenists, etc. see it as that they are just following the laws as laid down by a valid Pope, and it is rather the Cardinals who have invalidated those elections for the above stated reasons.
So your contention that the "pope was elected according to law". doesn't hold up even according to JPII and the Modernists! And things will only get worse from here because that group will also never allow anyone to forget it.
So while your "default" position would be correct in any normal time, clearly this situation is just as confusing or more than the Western Schism and droves of Catholics followed the wrong guy accepting him as Pope, but Pedro de Luna wasn't Pope after all. St. Vincent declared him a usurper once he saw that Pedro was not willing to submit to the Council - he had believed him to be Pope, then when he asked Pedro on the behalf of the King to step aside so the Council could unite the Church, he STUBBORNLY refused, Vincent who himself had literally dreams and visions and performed countless miracles was never told by God "That man is not the pope!" He simply saw that Pedro was not concerned about the potential for schism and had no real desire for unity. That was enough for Vincent to abandon him and start to preach against his claim - simply facts deduced by the damage Pedro would cause - thats it. Was St. Vincent in "danger" too?
The correct default position "generically speaking", is to acknowledge the papacy as what it is as defined by the pope's themselves and be desirous of submitting to a true Pope whenever/if ever the Church should get one again. The rest is just meaningless semantics used to

with all the puffed up egoism that goes with it.