In that quote, I think that they're subtly trying to change the meaning of "deliver".
Deliver means, "To bring or transport to the proper place". I think it's obvious that the man is bringing the letter to the proper place. If one is to argue that the letter is bringing the person to a particular place, then we have a problem with the word "deliver". If a letter delivers a person while a person delivers a letter, than any use of the word "deliver" would have to be reciprocal. A man delivers milk, and the milk brings the man there. A man delivers a pizza, and the pizza delivers a man.
I think that there is a dilemma where only two resolutions are possible:
a) the word "deliver" is always reciprocal
b) the word "deliver" is never recirpocal (and the quote is mistaken)
I prefer (b), myself, but I'd be interested in how the obvious third option can be arranged.