In an interview posted 12-31-14, Fr. Pfluger states:

we [viz., the SSPX] are forming a movement coming from the refusal of the reforms established in the wake of Vatican II. We represented the lifeboat for a good number of truly pious Catholics who, in the 70s and 80s, suddenly did not feel to be part of their church and who, for this reason, attached themselves to what they already held. But now we have to explain that we are no longer living in that time, that the situation has continued to evolve and that, therefore, we must continually reposition ourselves.

Quoted from the Fr. Niklaus Pfluger interview published in the SSPX magazine, Der Gerade Weg. (English translation) (bold emphasis and bracketed note added).