How does this not apply to your stated case? At Vatican I, this question was asked. The answer was "there was never such a case". How does Honorius suddenly become such a case? Wouldn't the Cardinals at Vatican I know the correct history of the Church? It is clear that Honorius' situation is not the same and Catholics need to stop using him as an example to "prove" that popes can be manifest heretics and remain the head of the Church.
Was answered by whom that there was never such a case? One cardinal who disagreed? The majority of assembled bishops?? A scholarly panel?
You are citing from a secondary source. We will be arguing in circles unless we have in front of us the actual proceedings of Vatican I, if such a thing is even available online. As for my part, I posted the actual Acta of the Sixth Ecumenical Council, which contains anathemas against Honorius as a heretic. Now if that is not what it looks like, then fine, but I need to see the entire justification for that, not just brief pull quotes.
And no, I am *not* saying the Pope can be a manifest heretic and remain the head of the Church. If he is a manifest heretic he loses the headship of the Church by that very fact—at least that’s how I understand it.
What I am saying is that Church’s official declaration of that fact can come years later, after he is dead and has been replaced several times over. But that is something the hierarchical Church needs to do, and not individuals.