Isn't Not the Poverty, Stupid

The NYT points out that homicide bombers are more well-off than the average.

A remarkable 57 percent of suicide bombers have some education beyond high school, compared with just 15 percent of the population of comparable age.

So it's the civil liberties of the country of origin. How about other factors?

Once a country's degree of civil liberties is taken into account ... income per capita bears no relation to involvement in terrorism.
Apart from the size of a country and the extent of its civil liberties, no factor that I could find — including the literacy rate, infant mortality rate, terrain, ethnic divisions and religious fractionalization — could predict whether people from that country were more or less likely to take part in international terrorism.