"First, throughout history, free-market capitalism has been a great driver of economic growth, and as my colleague Ben Friedman has written, economic growth has been a great driver of a more moral society.
Second, "trickle-down" is not a theory but a pejorative used by those on the left to describe a viewpoint they oppose. It is equivalent to those on the right referring to the "soak-the-rich" theories of the left. It is sad to see the pope using a pejorative, rather than encouraging an open-minded discussion of opposing perspectives.
Third, as far as I know, the pope did not address the tax-exempt status of the church. I would be eager to hear his views on that issue. Maybe he thinks the tax benefits the church receives do some good when they trickle down."
I had the exact same reaction that Mankiw had, and, as usual, Mankiw hit the nail on the head.