It is a truism which reflects human nature that we suffer from The Church as much as we do for Her. Recently the Vatican, apparently not being aware of SPPX Bishop Williamson's way unorthodox stance on the Holocaust (he is a Holocaust denier) included the man in a return-to-the-flock overture towards the SPPX.
Basically, here's the bottom line, and it ought to bring to a halt or at least give pause to those witch hunters with pitchforks and staves chasing Pope Benedict around the Vatican right now. He didn't know. From the NYT.
QUOTE In an interview in Thursday’s issue of Corriere della Sera, the Vatican official in charge of negotiations with the society, Cardinal Dario Castrillon Hoyos, said the Vatican had not known of Bishop Williamson’s views until after the revocation order had been signed. UNQUOTE
If so inclined, you may find more on this here
SSPX not satisfied with Bishop Williamson's apology
Bishop Williamson apologizes for ‘imprudent’ Holocaust remarks