Prima sedes a nemine judicatur. This is Canon 1556, which I failed to quote in my book, though I did state the fact of the law and the ecclesiastical admonition. These words mean: "The First Chair is judged by no one," which means that none of the pope's subjects are allowed to judge the status of him who sits on the throne of St. Peter. We may judge his theology and his public acts, as we are bound to judge the beliefs and ideas of everyone with whom we come into serious contact; but we may not judge whether he is the legitimate pope. Sedevacantists claim to be very expert about Canon 181, but Canon 1556 has somehow eluded them. - Fr. Wathen
Sedes are : Impatient - anarchists - and prone to lynching. They, themselves, are of no authority to do anything about these Popes except avoid their Masses, their bad advice or commands, and to pray for them. The Church in the future will evaluate and decide concerning the Vatican II Popes - then we will know the full of it all and will abide accordingly.
There is no knowing EVERYTHING that has gone on in these modern Pontificates - the Church will weed all this out in the future. There is much hidden, and in the background, that we do not know and that will make a difference. Let the future Church do Her work. That is how She goes about Her duty. The manner in which this will take place Our Lord knows, and is quite capable of accomplishing, though to us it seems impossible. "Why are you fearful, o ye of little faith?" - to the frightened apostles in the boat.
There is no knowing EVERYTHING of misinformation we have perhaps been given on these Popes that the sedes think they possess - even in the day of the Internet. For all we know of the full story, "Sedevacantism" could be a theory backed and promoted by Our Lord's enemies just to ensure confusion and discord in the ranks of those resisting their Vat. II Council. (And by the way, who is giving money to this sedevacantism movement and theory - is there some nefarious interest being the financial backer to this thing or these supporters?)
That is why we leave it to the future Church to deal with this. Meanwhile, we keep to our orthodox Catholic life as best we can in this age of Modernism.
God does not expect more of us than he would of, say, 12th century Catholics in a similar situation. No Internet there for finding out the hidden scoop and then presuming to make everyone somehow responsible for it. How about the Great Western Schism? Three different Popes with saints on the side of all of them, and souls supporting all three. Only one could have been the true Pope, and maybe none were. Did God condemn the confused, or those wrong in the matter? Did the holy saint go into sin over a bad choice and lose chance of canonization/salvation? No - the Church went on to the other side of the problem: She dismissed the three candidates and elected another, entirely separate one - behind whom all gathered. And the supporting saints of the various "Popes" were none the less holy or canonized for the experience. All the Church expected was for souls to keep the Commandments and Precepts - to keep personally their orthodox faith and keep free from sin. And then to back Her final solution to the crisis.
Sedevacantism is a good way for those wanting their own Church, nay territory to rule (say we, "kingdom"?), to have as an excuse for just going off on their own, and having to answer to nobody. How hard is obedience - how heady we can be! And with such anarchy goes their spirit of humility, meekness - and orthodoxy on other matters as well. They are judge, jury and executioner of the Vat. II Popes, though being NOBODY themselves - having no authority themselves. They take over the Church's job - Her future job.
And (often?) they actually say to boot, there is no salvation outside of Sedevacantism! They make matters worse, if such be possible. Some, maybe most, may mean well - but generally one is left to say: It's anarchy.