Archbishop Lefebvre was correct in rejecting Vatican Council II(Cushingism version) since a false premise was used in the interpretation.The false premise was never identified by the popes.Archbishop Lefebvre himself seems unaware of the false premise, similar to the four SSPX bishops and many priests of their community.
They had only to remove the false premise and Vatican Council II (Feeneyism version) becomes traditional.
Some priests of the SSPX Italy have made this change.Using traditional Feeneyism they say there are no visible exceptions to the traditional teaching on salvation.The baptism of desire etc are not visible exceptions.
Archbishop Marcel Lefebvre was excommunicated for rejecting Vatican Council II (with the Cushing premise). Cardinal Ratzinger never knew that a false premise was used.
As Pope Benedict XVI he also wrongly approved two theological papers of the International Theological Commission(ITC). They both carried the Cushing virus and he did not know it.
He issued the Notification against Fr.Jacques Dupuis S.J which was critical of the theology of religions, perhaps because Pope John Paul II asked him to do so.Otherwise he approved the theology of religions based on the false premise.It can still be read on the ITC website on line and has not been removed.
So we have the excommunication of an archbishop for rejecting correctly, an irrational version of the Council, which was not corrected by the Magisterium.
This was unfortunate and unintentional but it still was a scandal.Similarly the excommunication of Fr.Leonard Feeney was not lifted for some 19 years.The priest from Boston had rejected the false premise of there being known exceptions in invincible ignorance or the baptism of desire. For him there were no known exceptions to the traditional interpretation of the dogma extra ecclesiam nulla salus.
This was a scandal but the American bishops did lift the excommunication during the priest's lifetime.A Bishop officiated at Fr. Leonard Feeney's funeral Mass.In the case of Archbishop Lefebvre this was not done. He died excommunicated.
Both Archbishop Lefebvre and Fr.Leonard Feeney were excommunicated when their superiors were unaware that a false premise had been brought into theology, and this was being used to interpret magisterial documents.