St. Vincent Ferrer, who just happened to get the identity of the Pope wrong, he might as well have been a Satanist, and those Masses were sacrileges, displeasing to God. Or some guy in the Middle Ages who didn't know until a year later that the previous pope he had been putting in the Canon had died. And on and on.
No one is claiming that.
The AI post did not claim that.
The distinction was made - you just flat out missed it.
St. Vincent was not CONVICTED that Luna was a heretic.
None of the those papal claimant's were thought of as heretics.
Then it was only a material error about WHO WAS POPE not if this one or that one was a raging heretic.
You are comparing the material "apples" of that time/crisis to the "oranges" of this one.
Who is or is not named in the Mass as the Pope and Ordinary is something that should matter to all honest Catholics.
Maybe someone is honestly just mistaken or they didn't get the "memo" about who was now Pope, or they thought it was the wrong guy, etc.
THAT is WAYYYYY different then someone saying,
"I think Leo is a raging heretic and the Pope and now I shall go to Mass to worship God in communion with Leo united together in faith and in subordination to him."
Those are 2 TOTALLY different things.
But a nice cope goes something like this, "I think Leo is a raging heretic, I mean I see it daily with my own eyes he is really the dumps! Now I shall go to Mass to "pray" for Leo as the Pope NOT because I am united to him in faith, but because I think we should pray for him to be a good and Catholic Pope."
Now, is the above what many are doing without being aware that it MAY be a cope? Perhaps, that is for them to decide, based on the TEACHING (which did not just start with Fr. Cekeda on this issue, or even +De Lauiers, but the teaching predates them and the principle goes back centuries that one should NOT name heretics in the Canon, even if they are personally convicted only and no formal declaration has been made (as the above AI post denotes).