Perhaps His Excellency is drawing from the wisdom of Holy Scripture, particularly the end of St. Luke's parable of the rich man and Lazarus:
[27] And [the rich man] said: Then, father, I beseech thee, that thou wouldst send him to my father' s house, for I have five brethren, [28] That he may testify unto them, lest they also come into this place of torments. [29] And Abraham said to him: They have Moses and the prophets; let them hear them. [30] But he said: No, father Abraham: but if one went to them from the dead, they will do penance.
[31] And he said to him: If they hear not Moses and the prophets, neither will they believe, if one rise again from the dead.
This is a parable from Our Lord's own mouth, so no one can gainsay it. But to help explain it, keep in mind that Moses and the prophets were *full* of the supernatural and miraculous events. If someone could dismiss all that (the Israelites crossing dry shod over the Red Sea, manna falling from heaven for 40 years, etc.), one more person appearing from beyond the grave isn't going to suddenly make an impression on them.
To make my comparison explicit:
If the remaining Pfeiffer fanatics won't wake up to the reality about Fr. Pfeiffer after all that has happened (Ambrosegate, Pablo's constant nonsense, Fr. Pfeiffer's sermons from the past year and a half, etc.) then they're not likely to wake up even if +Williamson makes a formal, public statement about the group.
But just the act of TRYING to bury Fr. Pfeiffer for good, and not succeeding, will make +Williamson look bad and give Fr. Pfeiffer more political ammo (particularly by means of his Martyr and Persecution complexes).
Long story short, I think His Excellency has been most wise and prudent in his behavior thus far.