Hello Caminus, please consider the following points:
When Nestorius taught that Mary was not the Mother of God, the words themselves carried an objective meaning, one which needed to be denounced, and waiting for a juridical or canonical sentence to be passed on him would have been imprudent, for in doing so, Catholics would have subjected themselves to a heretic and thus fallen out of Catholic communion, being no longer Catholic. The objective sense in this case trumps the interior disposition, rendering it irrelevant.
The same can be said of the Eastern Schismatics when they rejected the Filioque, that there was not necessarily any conscious evil intent, but the damage of schism and heresy does not require conscious evil intent at all.
What I'm saying is that the internal dispositions of the antipopes matter not in the slightest, but the objective consequences of their apostate actions and teachings. There are enough decrees in the Tradition of the Church which tell us that these men are indeed not members of the Catholic Church, such as the following:
Pope Leo II, Third Council of Constantinople, 681: "...those who dare to compose another faith, or to support or to teach or to hand on another creed (Vatican II, for example)... excommunicated."