Dear Lover of Truth,
What has done the most damage to souls in the history of the Church is your one hair away from universal salvation belief, which is the common belief of even "traditionalist" sedevacantes persons like Fr. Cekada, CMRI, SSPius V, who are foaming liberals when it comes to BOD, for they TEACH that people are saved regularly every day by their false religion, and that although they don't know it, they are Catholics.
This belief has done the most damage to souls in the history of the Church because it is foundational to Vatican II's teachings on ecuмenism and religious freedom, which IS what Vatican II was all about. Vatican II has done the most damage to the Church of all heresies, and your one hair away from universal salvation belief is foundational to VatII. The reality is that people like you are the root cause of Vatican II, and you don't even know it or see it.
Bishop Lefebvre, Sermon at first Mass of a newly ordained priest (Geneva: 1976):
“We are Catholics; we affirm our faith in the divinity of Our Lord Jesus Christ; we affirm our faith in the divinity of the Holy Catholic Church; we think that Jesus Christ is the sole way, the sole truth, the sole life, and that one cannot be saved outside Our Lord Jesus Christ and consequently outside His Mystical Spouse, the Holy Catholic Church. No doubt, the graces of God are distributed outside the Catholic Church, but those who are saved, even outside the Catholic Church, are saved by the Catholic Church, by Our Lord Jesus Christ, even if they do not know it, even if they are unaware of it...”