Benedict knew the reputed 'Iron Bishop', Marcel Lefebvre. He was a giant on many levels, a virtuous prelate, a veritable giant in the mission field of the Church, a true religious and a saintly superior of the Fathers of the Holy Ghost. In many ways, Lefebvre had a charism to offer the Church in the confused years after the Council. His empathy and generosity in caring for vocations to the priesthood and care for the Sacred Liturgy could have been a great help to the Church. His greatness makes his collapse all that more frightening. These are frightening days, when even a great missionary and saintly prelate could be so misled as to end up dying outside the Church, an excommunicate.
In the mid-nineties, I attended a lecture given by an auxiliary bishop of Detroit, the Most Reverend Thomas Gumbleton, in which he notoriously rejected the Church's teachings on homosexuality. He instructed some 30 priests (I was only a seminarian, and had no way to protest it) how to do an "end-run" around the Church by discreetly assuring the homosexual in the confessional that they had done nothing wrong in committing genital acts with someone of their own gender. But no excommunication was ever issued for him. Instead, today, he continues to speak at conferences and writes for magazines, Several bishops consider him a Judas by refusing him permission to speak on Church property. Deo Gratias! But his sin, while grave and horrible was not, or is not to the height of making himself pope. Sinners abound in the Church of Jesus Christ … I know this from first hand experience of myself. But some sins are graver then others, and do great damage. This auxilliary contradicted the Vicar of Christ, but he did NOT claim to himself the authority of Peter. He is guilty of the sin of committing a secret schism, but he has not attempted to create an alternative Church.
Although I agree that schism is a very grave sin, my beef is that when excommunications are imposed only for schism, it gives the impression that the Church will only act if episcopal power is undermined. In other words, so long as you don't pull rank, you can do whatever you want in this Church.
So misguided women who try to get themselves ordained (small fry, really!) while clergy who denounce Church teaching aren't touched. It makes the Church seem like respecter of persons.