This is not complicated....and I wish to remind you that you are dealing with knowledgeable Catholics here, not the kind of people who will find your trivial revelations 'shocking'.
By the way, this is very important question. How do you know that you are "knowledgeable"? According to the Sentence of the Fifth Ecumenical Council,
in order to be knowledgeable, you need to investigate arguments of both sides, — than "the light of truth expels the darkness of falsehood":
But also the Holy Fathers, who from time to time have met in the four holy councils, following the example of the ancients, have by a common discussion, disposed of by a fixed decree the heresies and questions which had sprung up, as it was certainly known, that by common discussion when the matter in dispute was presented by each side, the light of truth expels the darkness of falsehood.
But on the matter of primacy of the Pope, Popes always avoided such discussion. For example, on the Council of Florence a discussion whether Ecumenical Council has more power than Pope, started only after departure of Greeks. And when Greeks were still present on the Council, they said that they think that Ecumenical Council has more power than the Pope — immediately before signing the final decree. Also on the Vatican Council the open discussion of infallibility was forbidden.
Than, if open discussion of infallibility never took place, — how can you be sure that you are "knowledgeable" until you investigate arguments of both sides?
And if someone wants to make such investigation of arguments of both sides — which books does he need to read?
I have full Russian translation of Acts of Seven Ecumenical Councils. And there is even no need to read them completely to make sure they are true. It is enough to read several pages of each volume, and you will see, how careful the investigation always was. But that is not so in case of primacy of the Pope.
A lot of what you're saying is highly debateable. The discussion of the pope's authority at Lyons II was fairly lengthy, which is understandable given how much of the prior proceedings were devoted to papal election and such. Granted, the question of infallibility didn't really come up so much as jurisdiction. That the question of pope vs. conciliar authority wasn't a big deal at Florence makes sense, given that this was settled from the Catholic point of view at Constance (despite what schismatics at Pisa/Basel/and so forth might have said).
Vatican I was hardly a model of tranquility, precisely because of the infallibility question. If it was such closed case, then the definition sought by guys like Cardinal Manning would have been a fait accompli. You talk about getting all sides of the story, yet your view of Vatican I seems to come right out of an Old Catholic polemic.
Your comment above
When the Church was already cut into two parts during thirty years, so that people in one part were out of the Church, no one of two Popes arrived to the Council to Pisa in order to heal the Schism, to stop a half of their flock being out of the Church. This was a legitimate reason for deposing both of them, because, according to the sentence of the Fifth Ecumenical Council, "not only the impious man himself is condemned, but also he who when he has the power to correct impiety in others, neglects to do so":
Our Great God and Saviour Jesus Christ, as we learn from the parable in the Gospel, distributes talents to each man according to his ability, and at the fitting time demands an account of the work done by every man. And if he to whom but one talent has been committed is condemned because he has not worked with it but only kept it without loss, to how much greater and more horryble judgment must he be subject who not only is negligent concerning himself, but even places a stumbling-block and cause of offence in the way of others? Since it is manifest to all the faithful that whenever any question arises concerning the faith, not only the impious man himself is condemned, but also he who when he has the power to correct impiety in others, neglects to do so. 1
1 This, of course, refers to Pope Vigilius.
Your footnote is an extrapolation as there is nothing in the acts of the Council itself that indicates this is a shot at Pope Vigilius. In fact, if you keep reading, the Council is quite deferential to him calling him things like "most religious" and "his reverence" and saying how much was done to persuade him of the badness in the writings of Theodore. If the Council is the supreme authority, why did Vigilius specifically need convincing? I don't recall language like that in any other council about any other patriarch. The emperor was already on board, which was clear from his persecution of western clergy. Yet still Vigilius delayed and all other parties waited for his confirmation of what had been decreed. Why? The answer, of course, is because Vigilius wanting to make sure that whatever decision was rendered would conform with Chalcedon (hence his second "Constitution").
On another note, why bother specifically singling out the fact that it's ok to condemn heretics posthumously because that's what Rome has done? What makes Rome special?
Let me conclude by saying that I don't consider myself all that knowledgeable. I know a bunch of Eastern Orthodox and Eastern Catholics. When my wife was Protestant, she considered converting to Orthodoxy for a long time. We went to the Divine Liturgy in both Greek and Antiochian churches. My point is that I've been exposed to what a lot of Easterners have to say about things.