After every Islamist bloodbath, we hear from Muslims and the Mother Jones/Daily Kos crowd that religion had no role in the slaughter. The Charlie Hebdo massacre again brought out some well-intentioned protesters who insisted on severing the criminals from their Islamic inspiration, despite the fact that the killers shouted “Allahu Akbar” and “We have avenged the prophet!”

Said a French Muslim named Diallo,

This is not a question of religion. It’s a personal problem, and in fact it doesn’t have to do with Islam.

Stateside, Kareem Abdul-Jabbar asserted the same thing in a piece for Time magazine.

Knowing that these terrorist attacks are not about religion, we have to reach a point where we stop bringing Islam into these discussions.

This almost unbelievable blind spot is pervasive, but there are also plenty of religious or cultural Muslims like Maajid Nawaz, Fathima Imra Nazeer, Kaveh Mousavi, and Ali A. Rizvi, who’ve transcended the myopia and aren’t afraid to call out Islam as a huge part of the problem.

Add another name to that list: Hassan Hassan, an analyst at the Delma Institute, a research center in Abu Dhabi. Hassan, who’s written for the New York Times and the Daily Beast, and Michael Weiss, a columnist with Foreign Policy, wrote a book together: ISIS: Inside the Army of Terror. It will be published next month. In a piece for the Guardian, Hassan shares some of the the results of the duo’s research.

As part of research involving in-depth interviews with ISIS members for a book about the organisation, American analyst Michael Weiss and I have identified half a dozen categories of ISIS members according to the factors that drew them to the group. In at least two of those categories, religion more than anything else has been the driving force. But these two demographic components — long-standing takfiris (radicals who adhere to teachings that declare fellow Muslims as infidels) and young zealots — are more central for ISIS than other members because they formulate the group’s identity and ensure its resilience. … “We spread our message by proselytisation and sword,” [said one of the interviewees]. “Ibn Taymiyyah said ‘the foundation of this religion is a book that guides and a sword that brings victory.’ We guide and the sword brings victory. If someone opposes the message of the prophet, he faces nothing but the sword.”

But surely this is a perversion of the real, peaceful Islam? Not so, conclude Hassan and Weiss.

In terms of indoctrination, ISIS generally steers clear of exposing new members to teachings that are not derived from sharia texts. New members are almost exclusively exposed to religious books, while established members or commanders can study manuals such as Management of Savagery, a jihad book written by an Abu Bakr Naji, who said that you should distinguish between jihad and other religious tenets in that jihad is not about mercy but about extreme retaliatory violence to deter enemies. The restriction of religious training to religious texts is in line with the group’s rhetoric that it is an extension of authentic Islam rather than a new group with its own set of teachings. Indeed, … ISIS presents the “mainstream” Islam practised by Muslims today as one that was “invented” over the past few decades. To unravel this so-called invented Islam, Isis deliberately digs deep into Islamic sharia and history to find arcane teaching and then magnify it. It does so to shock its potential recruits and demonstrate it is preaching a pure and true Islam obscured by the mainstream.

Take the little-practiced phenomenon of throwing men accused of being gay off the roofs of tall buildings, as ISIS did earlier this month in Mosul, Iraq.

Unlike previous incidents of stoning adulterers and crucifixion, throwing people from high buildings did not even inspire criticism of sharia in the Middle East because many did not realise it was a sharia penalty in the first place. But it is the obscurity of the punishment that makes it particularly valuable for ISIS. The purpose is not to increase the volume of violence but also to raise eyebrows and trigger questions about such practices, which ISIS is more capable of answering than mainstream clerics, who prefer to conceal teachings that propound such punishments. Many ISIS members were eager to emphasize they were impressed by such obscure teachings, and were drawn to the group by the way ISIS presents Islam with absolute lucidity. [One adherent] spoke about the group’s “intellectualism and the way it spreads religion and fights injustice.”

Nothing to do with Islam? Weiss and Hassan beg to differ.

The argument that these acts are not Islamic often ignores how such stories are told. For instance, ISIS tells the story of Muhammad’s commander-in-chief, Khaled bin al-Walid, who killed hundreds of captives after the 7th-century battle of Ullais in Iraq, seemingly contrary to Islamic teachings, because he had made a pledge to God that he would make a river of blood from the Persian army if he overran it. When he could not find enough people to make a river out of their blood after he defeated them, he killed the captives and opened a dam into their bleeding bodies. ISIS uses the story to say this is the man described by the prophet as the Unleashed Sword of God and who was praised for his victory in that battle by the first Muslim caliph, Abu Bakr. When ISIS kills its captives, a Muslim cleric can dismiss the act as un-Islamic, but ISIS can simply cite the example of al-Walid. Because ISIS bases its teachings on religious texts that mainstream Muslim clerics do not want to deal with head on, new recruits leave the camp feeling that they have stumbled on the true message of Islam.

After the 2013 Boston bloodbath, Ali Rizvi wrote:

In the aftermath of the Boston Marathon bombings and the foiled al Qaeda-backed plot in Toronto, the “anything but jihad” brigade is out in full force again. If the perpetrators of such attacks say they were influenced by politics, nationalism, money, video games or hip-hop, we take their answers at face value. But when they repeatedly and consistently cite their religious beliefs as their central motivation, we back off, stroke our chins and suspect that there has to be something deeper at play, a “root cause.” The taboo against criticizing religion is still so astonishingly pervasive that centuries of hard lessons haven’t yet opened our eyes to what has been apparent all along: It is often religion itself, not the “distortion,” “hijacking,” “misrepresentation” or “politicization” of religion, that is the root cause.

I fear these words will have to be repeated millions of times, following thousands more Islamist atrocities, before they’re understood in sufficient numbers to begin making a difference.