In our day there are a lot of people who call themselves, and mean to be, traditional Roman Catholics. Yet a great many of them do not hold to the traditional Catholic understanding of the Papacy, either because they do not know it or because they unhappily accept the “Popes” after Pius XII as valid and legitimate but know that they cannot submit to them without abandoning the traditional Catholic Faith.
Every sedevacantist bishop was consecrated without a papal mandate which is forbidden by the 1917 Code of canon law, and every sedevacantist priest says mass and hears confessions without faculties, which is also forbidden by the same Code. Sede priests and bishops recognize Benedict XV's papacy as legitimate, yet resist laws he promulgated in the 1917 Code
every single day. And what I mentioned are only a few of the laws they violate on a daily or weekly basis.
Fr. Cekada wrote a book tearing about the liturgical laws of Pius XII whom he recognized as a Pope, and refused to use the missal he promulgated.