As you can see from Biggirl’s response, most modern day Catholics don’t think other Christians need to convert. Like VII, they believe that Christ’s Church only subsists in the Catholic Church. Other Christians are a part of Christ’s Church, just imperfectly so. They are partially in communion. They just don’t have the “fullness of the Truth”. Christ’s Church lacks unity.
Catholics who ARE Catholic KNOW that the SSOPX schismatics need to convert to Catholicism. Do you?