"The Bishop, within the bounds of what is properly lawful, sets the conditions for ordination and for the pastoral oversight of clergy and all who hold his licence. No one, under their oath of obligation, can turn round and say that they are not willing to accept the rule the Bishop makes and expect, nevertheless, to proceed to ordination."
(via Chelmsford Anglican Mainstream)
For background on why +John is saying this, go here. In essence, an ordinand refused to share communion with Bishop John, and so Bishop John is not prepared for him to be ordained in his Diocese. Which seems fair enough to me.