Bp. de Castro Mayer had a break with Dr. Plineo of TFP and determined that he was "anti-clerical'.
But the American TFP. as a lay apostolate, has publicly processed the Faith annually in the form of Rosary rallies. exceeding 22,000 locations.
Far, far in excess of anything the SSPX has ever done. The fact is. it is the Catholic layman who is responsible for carrying the Banner of the Faith.
Every Mass said in good standing is the most supreme profession of Faith.
So in all the years the SSPX and its allies said Masses, up until they decided to jump in with the Modernists, was a profession of Faith.
TFP are a world in unto themselves. Very bizarre, and tell their members it's ok to attend the novus ordo. (On a regular basis, and not just some throwaway remark under pressure. )
The Church cannot survive without clergy.
The one, simple job of a Catholic layperson who realizes the Crises in the Church, is to seek out the remnant clergy, and to align themselves, at least spiritually with them. To sanctify the Sunday when they cannot get Mass on Sunday, and to actively stay in contact with Resistance (remnant) clergy.
TFP have made Plineo their practical Pope. They are therefore the definition of a cult, and should be avoided in matters of religion. Though the produce excellent material on modesty, etc. etc.