Perhaps, Gunthr, because a larger number of Muslims are poor, live in countries whose ruling class wouldn't look out of place in feudal Europe and will never relinquish any power to the populace. Add to this a lack of education, deliberate propaganda from terrorist, extremist groups in the poorer areas of the world. The existence of huge, dispossessed groups such as the Palestinians who are seen as an untermenschen by a Western supported government, with a level of human rights provision a Westerner would never accept. Nationalism and a feeling of injustice is used to fuel a fury aimed at those who perpetuate it - religion becomes a unifying power, as it has done many times before. Those in a position to do something about it, outside of strapping semtex to their torso and going on a bus ride, fund or fund-raise for organisations set-up to 'redress the balance'. These individuals tend to be highly educated religious nut-jobs who believe they have a mandate from the Islamic world for their actions. To some extent they probably do.
Perhaps those things have something to do with it, but I'm no expert.
