Original post by SuetoniusI'd say a mixture of crazed exultation, social propaganda, perverse childhood "development", literalist readings of religious texts, and so on. The thing itself is not created by Western foreign policy in any case. The strands of thought, and the movements that hold them, have been in existence for over a millennium: through the Caliphate, the Islamist Ottoman Empire, writers such as Wahab and Qutb (even Khomeini and his 'velayat-e facqui' to an extent). The Islamist claim that a theocratic regime must spread by means of violent jihad* simply does not directly follow from any Western intervention in the region, nor can it be considered a rational response. It is completely sui generis. To use another example, it may well be said that had the Iraq war not taken place the mosque at Samarra would not have been blown up by Al Qaeda psychopaths in 2006. But the idea that all Shia be deemed impure - and practically subhuman - is not a direct consequence of Western foreign policy. That also predates it. As does fundamentalist anathematising of all Hindus, and the subsequent attempts to blow up the Indian parliament (in 2001) and Bombay (in 2008). Similarly, you see mosques being blown up in Pakistan on a weekly basis, where the U.S. has not invaded. Remember, the main victims of these movements are not Westerners, or Israelis, but other Muslims (spanning a range of countries: Mauritania, Mali, Somalia, Algeria, Nigeria, Libya, Tunisia, the Phillippines, Malaysia, Indonesia, and so on; plenty of these countries being staunchly opposed to U.S. foreign policy). Al Qaeda are an imperialist bloc that wants to impose a Taliban-esque regime on the entire Ummah. These ideas are not a direct outcome of Western involvement in the Middle East in the same way that, for example, Pan-Arabism (or other forms of nationalism) are. Similarly, there are many other countries on earth that have been invaded, occupied and plundered by Western hegemonic interventionism that have not seen psychopathic criminal behaviour of the jihadist kind. When the United States supported the apartheid regime, for example, Nelson Mandela didn't use a tribalistic, mediaevalist form of Christianity in order to condone the throwing of acid in the faces of teenage girls, genital mutilation, suicide bombing or beheading. The same can be said of the NLF in Vietnam, the various resistance groups in Rhodesia, Fretilin in East Timor, the supporters of Allende in Chile, the Nicaraguan Sandinistas etc. Similarly, you don't see Cuban exiles launching suicide campaigns or "holy wars" against Fidel Castro in the same way that Chechan Islamists unhesitantly slaughter over a hundred schoolchildren in Beslan because of their belief that God is on their side. You don't see the Kurds attacking Iraqi society for what has been done to them over the past 30 years (poison gas, genocide, expulsions, mass graves), by blowing up Baghdad's UN offices and churches, suicide bombing in busy market places and funeral processions, cutting off the water supply, sabotaging elections etc. 'Al Qaeda in Iraq' (many of whose members aren't even Iraqis) are busy doing that. You really are looking at the face of evil with these religious fanatics. What we are truly up against is a form of imperialistic fascism, and no capitulation or appeasement on our part will deter them.
*as Iran's constitution explicitly states
P.S. The OP's so-called argument is obscenely post hoc ergo propter hoc. There is no direct causation between U.S. sanctions on Iraq (which were intensified to fatal levels by Saddam Hussein's own negligence, and refusal to make goods available to feed his own people while he was building a palace in each of Iraq's eighteen provinces) and the actions of the Saudis and Yemenis who committed that terrible atrocity. None of the 9/11 hijackers had any ancestral or familial relation to Iraq (just as none of the 7/7 bombers had any ancestral or familial relation to Iraq or Afghanistan). Indeed, if you say they felt solidarity with dying Iraqis during that period because of their mutual religious beliefs, then this obviously shows once more that religion is the ubiquitous and overarching problem. As it happens, I don't believe the sanctions had any bearing on the hijackers' motives.