Doesn’t Bishop Tissier approve what they say?

In part, perhaps, but they will never say that Bishop Tissier disapproves completely their going away from their assigned post, and disrupting the little army of the SSPX.

 
...To tell you the truth, [Bishop Tissier] still does not, to this day, agree with what I am doing. He wrote to Fr. Pivert (my spiritual director) to coerce me, repeating the same argument, in writing this time, namely that the errors of bishop Fellay are 10 times as many as they appear in public and that the General Chapter is a disaster, but that there is no reason to launch such an untimely attack against the SSPX management.