Archbishop himself articulates the problem this poses for indefectibility, and this consideration is what left him open to the sedevacantist hypothesis ...
Nonsense:
You invent advocates and sympathizers left and right for sedevacantism because you intuit the weakness of the position.
The fact remains that there were only 2 instances in 25 years of thoroughly recorded and publicized sermons, conferences, articles, books, and interviews in which ABL (rightly or wrongly) seems to acknowledge the theoretical possibility of sedevacantism.
Both those instances followed upon the heels of extremely scandalous Roman acts, but you habitually fail to impute any significance to the fact that ABL never backed those statements later, and certainly never supported sedevacantism habitually (and in fact condemned the position officially).
The proper hermeneutic in understanding the mind of an author is that the exception does not disprove the rule (ie., it cannot be used to contradict his normal, general, and overwhelmingly common position regarding sedevacantism).
It is therefore dishonest to attempt to magnify these two particular instances as though they evince a general tolerance (or even sympathy or promotion) of sedevacantism.