In "A Very Old Man with Enormous Wings," why is the delay from the Vatican symbolic?

Despite the
general agreement that the old man is an angel, letters from Rome show disinterest, and even a
certain amount of mockery. It seems that the Vatican is not convinced, and so they delay until
they stop receiving letters, not wanting the expense of sending a high-ranking official
out:

...the mail from Rome showed no sense of urgency.
They spent their time finding out in the prisoner had...