I wonder how many of them are truly moved by the traditional Mass and how many of them do it once or twice to "demonstrate" to the local "traditional community" that they are "friendly" to tradition and then go right back to their balloon masses. Possibly...all of them?
When a Conciliar bishop says the traditional Mass it is almost always (if not always) for show. They really and truly see no intrinsic value; it's just the preference of a small minority that they feel they have to placate.
The Conciliar bishop who says the traditional Mass once and then returns to the service he really enjoys where he can express himself and watch the adoring faces of his fans is, I think, worse that then bishop who spurns the traditional Mass completely. At least the latter isn't making a mockery of the Holy Sacrifice of the Altar.