What Canon Law envisions is a straight defection from the faith and not heresy per se, where an office-holder were to get one day and say he's converted to Eastern Orthodoxy.
In general, the thesis is well argued by a man who was arguably the top theologian in the Church prior to Vatican II, +Guerard des Laurier, and I love it how armchair hacks can sit here and think they've refuted it in a couple sentences.
I love it when public defection doesn't mean public defection but something else more nuanced, hyper-qualified, in a legal context, blah, blah, blah.
I don't need to be a canon lawyer to know what
publicly defects from the Catholic faith means. When every Catholic with a brain cell and an ounce of faith flees from the man as a vile heretic, that means he has publicly defected from the faith.
Bergoglio and Wojtyla have done their best to prove in every way possible that they're not Catholic. I don't believe in legal fictions where someone can be "legally Catholic" while worshipping demons of his own free will.
Sedevacantism is simple: non-Catholics can't be Popes, leaders of a new religion can't be Catholic.
Sedeprivationism rests on so many unsupportable premises, fine definitions and sheer nonsense it can only be convincing to an "educated person".
Just like "uneducated neckbeards" can't be convinced of evolution but an "expert" is thrilled to play with the intriguing novel theory.
Catholics: God created the world and everything in it. -- SIMPLE.
Heretics: So, first there was this singularity (insert nonsense definiton)... there's this process called mutation (there are positive and negative...)... if you give it a billion years... through natural selection... -- CONVOLUTED.
Sedevacantists: Heretics can't be popes. The See of Peter is vacant. -- SIMPLE.
Sedeprivationists: First we have to understand the distinction between the
matter and
form of the papacy... So then this heretic, who's legally a Catholic, was
designated as
pope-elect... but he has an
impediment, a
contrary intention to impose a false religion on Catholics (which doesn't make him a heretic mind you, he's still
papabile)... according to canon law... -- CONVOLUTED.
When your answer to the crisis is a 50-page doctoral dissertation (or thesis

) that nobody understands (that's why they're constantly
"explaining the thesis") except ten people from the Most Highly Trained seminary you can bet it's a bogus theory.