yes, a heretical Pope loses membership in the Church, but one needs to prove he is a formal heretic, not just a material heretic (which you can't do).

Whoah...
Here we see a very common tactic used by adherents of the resistance position: As they are usually quite unfamiliar with Catholic magisterial teaching on the Papacy and can’t be bothered to look it up, they instead make up their own inept arguments from Sacred Scripture or other sources which they think lend support to their thesis.
So the claim is made that Christ never stripped Caiaphas the High Priest of his office, despite his official rejection and condemnation of Him (see Matthew 26:57-66). This, the resistance adherent triumphantly believes, is the death blow to Sedevacantism!
There is just one problem with it: It isn’t true. Christ did strip the high priest of his office. More specifically, the high priest stripped himself of his office, by his own act of apostasy, the sentence being rendered by the divine law (thus Christ’s) itself.
Don’t take our word for it, though; take the word of St. Jerome, Doctor of the Church and patron saint of Bible scholars, commenting on this passage in St. Matthew’s Gospel:
In other words, St. Jerome tells us that when the high priest Caiaphas rent his garments and rejected Christ as the true Messias, he lost his authority and his office, automatically and without a declaration, by publicly defecting from the true religion. Does this sound familiar or what?
Of course we can have a bad Pope. What we cannot have, however, is a non-Catholic Pope — just as we can have a bad Catholic but not a non-Catholic Catholic because that’s a contradiction in terms.

If Christ didn't die, you would have a case.  But Christ did die at the hands of heretics to which He was obedient unto death.  And so was His mother.  

So, Ladislaus won't accept those approved Catholic books, and because I won't listen to him telling me I shouldn't either, I am "heretically depraved filth"!

The current crisis is a mystery which we are not held accountable for solving it.

Then why do all of you anti-sedevacantists insist that we must be able to resolve the Crisis?

Are you seriously comparing the SSPX position on the Pope with Arian heresy? It is beyond absurd (and I don't see how the Arians could have taught their error in good faith, certainly not after the Council of Nicaea and its approval of a creed with homoousios).

....in the sedevacantist scenario the Church has failed by having no more bishops with ordinary jurisdiction which results in cessation of the Apostolic Succession (some sedes understand that and hold onto what Fr Cekada called "bishop in the woods" theory - somewhere there is a bishop with ordinary jurisdiction, but no one knows who he is and where he is). Obviously I will not accuse sede clergy of formal heresy for teaching that error, because I know they do it in good faith, just like its absurd to accuse the SSPX of formal heresy.

Again, thinking that sedevacantism provides a comprehensive explanation of the current crisis is nothing but a delusion. It is a possible, but problematic thesis which fails to answer important questions, just like R&R fails to do so. The current crisis is a mystery which we are not held accountable for solving it.