This is absolutely correct. THIS is where private judgement has a legitimate role, in examining the motives of credibility. Traditional Catholics look at the Conciliar counterfeit Church and recognize that it lacks the Marks or Notes of the One True Church found by Christ.
Interesting that the Protestants arrived at the same conclusion about the Roman Catholic Church after the Council of Trent. They maintained that the Church post-Trent was a New Church that taught a New Religion, just like the Sedevacantist heretics believe the Church post-Vatican II is a New Church that teaches a New Religion. There is another parallel between the Protestants and Sedevacantists.
If the Roman Catholic Church - i.e., the Church of Rome and all the particular churches throughout the world in union with it - lacks the four marks, where is the infallible, indefectible Church with four marks, outside of which there is no salvation?
I've been asking Sedevacantist heretics this question for years, and all I ever get in reply is a blank stare.