Archbishop Lefebvre did not call the Pope himself a heretic. He stated the "See of Peter" and "posts of authority" in Rome were occupied by Antichrists. That is not the same thing as referring to the Pope at all. The "See" means merely "Seat"--it is a place, not a man. It is a term used metaphorically and diplomatically--just as we use the term "White House" to sometimes mean the staff of the President and sometimes to mean the President himself. It is deliberately vague and ambiguous. In this case, the term "See of Peter" has been qualified by the plural "posts of authority", which makes it clear he is talking about high officials in Rome and not the Pope. In no instance did the Archbishop call the Pope himself either a heretic or an antichrist. In fact, if you knew anything at all about Lefebvre, you would know he cautioned just the opposite and forcefully rejected sedevacantism among his followers. Archbishop Lefebvre never crossed the line you are suggesting he crossed. There is nothing you have posted to indicate otherwise.
*LOL When Lefevbre said that an antiChrist was occupying the "See of Peter," do you thinkhe was referring to Dan Rather?
With all due respect, your "explanation" is insane.
The Apostolic See...
From ancient times a distinction has been made between the Apostolic See and its actual occupant: between sedes and sedens. The object of the distinction is not to discriminate between the two nor to subordinate one to the other, but rather to set forth their intimate connection. The See is the symbol of the highest papal authority; it is, by its nature, permanent, whereas its occupant holds that authority but for a time and inasmuch as he sits in the Chair of Peter. It further implies that take supreme authority is a supernatural gift, the same in all successive holders, independent of their personal worth, and inseparable from their ex-officio definitions and decisions. The Vatican definition of the pope's infallibility when speaking ex cathedra does not permit of the sense attached to the distinction of sedes and sedens by the Gallicans, who claimed that even in the official use of the authority vested in the See, with explicit declaration of its exercise, the sedens was separate from the sedes.
* any sane individual can see lefevbre was calling the Pope an antiChrist. That is a heresy