Most people known to be associated with the terrorist activities come from the privileged or middle classes - they have money, education, social connections, they travel abroad, and study in foreign universities. Could you please explain how they are "oppressed."?
What is more, if the "oppression" explanation were true, how come that the US has not been terrorized by Latin Americans (where the US behavior was truly deplorable) but has been terrorized by Middle Easterns, even though the US role there has been quite beneficial (cf. preventing the European retaliation for the nationalization of the Suzez Canal by Naser, forcing the return of Sinai to Egypt, liberation of Kuwait, not to mention a steady influx of petro-dollars)?
The proposition that oppression breads resistance and the US is a just target of that resistance belong the the realm of morality play - not a materialist analysis.
wojtek