Blogger Razib Khan (always worth reading by the way) has a couple of long posts on ISIS, Islamic exceptionalism (and non-exceptionalism) which are well worth a read.

Excerpts:

ISIS Will Win Many Battles But Lose the War

..But just as economic and social marginalization fuel disaffection among Europe’s Muslims, many elements of Islamic religious theory and practice are easily co-opted into justifying violent movements. Islam after all is a pacific religion historically only after it has dominion. Even if one rejects the proposition that Islam is the reason for violent terrorism by Muslims, one does not therefore accept that it is no part of the overall dynamic.

Group solidarity around a compelling meta-narrative is the important “big picture” element of Islamic terrorism which is critical toward understanding its motivations, and which can be missed by descriptive ethnographies or econometric analyses. [Fig 4]​ Palestinian nationalist terrorism of the 1970s, or Tamil Tiger suicide bombing of the 1980s, were fundamentally derivative or subordinate to a broader family of ideologies, post-colonial nationalism with a Leftist inflection (ETA and the IRA also fall into this category, even if situated in the West). In contrast, Islamic terrorism has the potential to become superordinate, and swallow up individual movements and grievances into a meta-narrative. E.g., the core actors in ISIS to this day seem to be a shadow of Saddam Hussein’s Baathist officers. It is neat to presume these individuals are using Islamic ideology in an instrumental sense, as Saddam [8]​ himself clearly did. But the Islamic meta-narrative is powerful, and has historical precedent. It is plausible that though the trigger for the precipitation of an Islamic movement in Iraq was the defenestration of the officer core of a notionally secular national regime, the ultimate crystallization and end state of the movement may be toward a sincere and genuine Islamic nationalism.

....But the likelihood is that the core Islamic world, from Morocco to Pakistan, will be riven with conflict and tumult, and that will draw in Diaspora populations, and those from the demographically important margins (e.g., Indonesia). This conflict will spread back out to non-Muslim nations with Muslim minorities. As Atran notes all one needs are a small motivated number of young men to allow for their to be critical mass for violence. Some level of violence directed toward majority non-Muslim populations in nations with large Muslim minorities may be inevitable. For non-Muslims the fact that the vast majority of Muslims decry violence, both due to sincerity and self-interest, will be somewhat besides the point, as the violent minority are going to take center stage in national concerns. In the Muslim world the violence will be orders of magnitude worse, just as the fascist and communist regimes of the 20th century inflicted most of their terror upon the populations whom they ruled. In an almost Newtonian fashion I expect that non-Muslim societies under attack from Islamic international will exhibit a more self-conscious cultural identity than before in reaction.

There Is No Exception in Islam

..Several years ago there was a famous exchange between Ben Affleck and Bill Maher & Sam Harris on the nature of Islam. In response I published a post titled “ISIS’ Willing Executioners”[1]​. The overall point was that Affleck’s comments were not informed by the nature of Islam or Muslims, but broader political currents. As for his interlocutors, Bill Maher and Sam Harris, I think they were making a better faith effort to engage with the facts, though they too came up short. .

....On both the American Left and Right there is a tendency to not even attempt to understand Islam. Rather, stylized models are preferred which lead to conclusions which are already arrived at. Islamic Exceptionalism [5]​ is worth paying attention to because he frankly admits the problems of this line of thinking. Or, more honestly, he admits that this is a problem in the first place!
..In terms of the historical and religious narrative [1] naturally argues that Muslims are the exceptions. I take exception to this. Rather, I think the Western liberal model based on a creedal Protestant church is the exception. .

..But how those facts came about, and why, that is a different matter. The Islamic world is here. And it will be difficult to move it elsewhere. By making it seems as if being here is inevitable, Hamid seems to be arguing that moving it to a different equilibrium will be exceedingly difficult. But if you posit that modern conditions are historically contingent and labile, then the future is less predictable. I am come not to bring answers, but the cloud of confusion.