You sedevacantist privationists need to be consistent in what your brand of sedevacantism is exactly. Ladislaus also considers himself to be a sedeprivationist, but he also believes that I am a heretic if I believe that Francis has jurisdiction.
Ladislaus too believes that Fr. Chazal backs up sedeprivationism. Not good.
Sedeprivationism is indeed a form of sedevacantism. In the thesis, the conciliar popes are NOT true popes, because the indefectibility and infallibility of the Church prevent us from saying that a true pope could ever promulgate false teachings, false liturgy, evil disciplines, etc. The errors that traditionalists perceive "officially" emanating from Vatican II.
The distinction is that among sedevacantists, there are "
totalists" and "
material-formalists" (also, those who can be said to be merely "opinionists" but still attending the SSPX, or such). The totalists say that Bergolio is not pope in any way, that is, he has neither the papal jurisdiction nor even a valid election. The
material-formalists (this is, the sedeprivationists) say that he is not the pope because he lacks the jurisdiction, but that he does possess a valid election, and therefore, have the potential to become the pope.