The letter is a response to evangelist Pat Robertson's assertion that Haiti has been "cursed by one thing after another" because the Haitians made a pact with the devil to break free from French rule in 1804. ("True story," Robertson said.)
As Coyle points out, people who make a pact with the devil are supposed to pay up in the next life, not in this one.
The question of why bad things happen to some people but not to others is a fundamental one.
A popular answer is that people who suffer have offended God in some way.
The Bible, specifically Genesis 3:16, explains the pain of childbirth as part of the punishment women must suffer for the sin of Eve, who with Adam disobeyed God in the Garden of Eden.
Not only that, but the Talmud, a collection of rabbinical writings, says that women who die in childbirth have violated Jewish law in specific ways. Imagine the neighbors trying to figure out exactly what transgression the dead woman might have committed.
Here's my two cents: Bad things happen to good people. All the time. We don't know why, but they do.