No one but God can read the internal forum with absolute certitude.  A judge declaring a heretic only needs moral certitude.

Right.

and a morally certain judgment must be followed.

 Nobody can judge the internal forum with any degree of certitude ... other than someone with a supernatural gift

We follow judgments regarding the extrenal forum, and the Church can discern a non-pope based on their pertinacious adherence to heresy, whether or not they are in good faith, sincere, insincere, evil Satanists bent on destroying the Church, or well-meaning morons.  What the case there happens to be means nothing, since we cannot know this with any degree of certitude unless these things make it out to the internal forum, i.e. someone intercepts a letter from Wojtyla bragging about how he's serving Satan and trying to destroy the Church.

So, if you know his history, that's not what he meant at all.  He holds that Bergoglio and Prevost are Anti-Popes, but that Ratzinger / Wojtyla were not.  As evidence for Bergoglian heresy he and his guru (Father Kramer) cite (among other things, but this was the first thing Fr. Kramer used to discern Bergoglio to be Anti-Pope) Bergs' denial of the teaching of the Council of Florence by claiming that the Old Testament remains in force, has not been revoked, and is salvific for the Jews.

So I point out that Wojtyla actually invented this heresy, taught it repeatedly, and then Ratzinger taught it repeatedly, his responds by insisting that those two didn't really mean it ... whereas Bergoglio does.  Ridiculous.  But it's his act of desperation to upholds his theological worldview that the Bergoglio and Prevost are the Crisis in the Church, and Anti-Popes, but the predecessors were not.  If anything, Wojtyla / Ratzinger are likely MORE guilty since Bergoglio is a moron who appears to just regurgitate what the others taught and invented, but those predecessors of his were well educated prior to Vatican II and were the INVENTORS of the heresy, so if anything it's the exact opposite.