If I were Bishop Williamson, I would have responded with an open letter that, "For the good of the faithful who depend upon you, I will grant your request for the Holy Oils, but this should not be construed as an endorsement by myself of your various theological positions." I think that His Excellency should rise above the personal disagreements with Father Hewko for the sake of the faithful.
At the same time, Fathers Pfeiffer and Hewko should also have kept their disagreements with Bishop Williamson much more civil than they ended up being. It's obvious that the primary animus driving their hostility was Bishop Williamson's refusal to consecrate Father Pfeiffer and to endorse his seminary, and so various matters that should have been respectful disagreements transformed into hostile attacks, and Father Hewko was largely dragged along by Father Pfeiffer's stronger will.