The Barcelona attackers killed 14 people—a middling tally for an ISIS attack in Europe. Watch one of the attackers prancing around like an idiot on the streets of Cambrils, Spain, before being shot dead by police, and you can see why the death toll might not have been higher. These do not appear to be trained commandos, moving calmly and tactically like the Bataclan attackers in November 2015. They are amateurs, and if they had any training at all, it doesn’t show.

The biggest concern for counterterrorism officials, and indeed anyone interested in not being blown to smithereens in a Brussels subway or shot dead in a Parisian theater, is the returned foreign fighters—those who went to Syria, were taught to kill, and have returned to their home countries. Since we still don’t know much about this population, and still less about those who have come back, every last morsel of information about them deserves close scrutiny.

Last month, the United Nations office of Counter-Terrorism issued a report on the foreign fighters who left for Syria. Hamed El-Said and Richard Barrett, authors of “Enhancing the Understanding of the Foreign Terrorist Fighters Phenomenon in Syria,” sought foreign fighters from the Islamic State—returnees from Syria, plus a few who were caught trying to get there. (One of those who didn’t go listened at the last minute to his mom’s pleas to stay home. It’s difficult to say whether she deserves a Good Parenting award for saving her son’s life, or a public shaming for raising such a foolish kid in the first place.) Over 40,000 people have traveled to Syria to fight, and since many of them will return to their countries of origin, studies like this are worth reading even when they are, like this one, deficient in ways the authors themselves acknowledge. The flaws are more interesting than the findings.

The authors talked on the subject of jihad to exactly 26 people, with another 17 declining to answer questions on jihad (but willing to talk about other aspects of their journey). If those numbers sound comically small, I urge you to cut the report’s authors some slack. As they note, it is hard to find anyone at all to talk about their apparent membership in a terrorist cult. All previous surveys have had the same problem of a tiny sample size. Even with the backing of the United Nations, the authors could persuade only seven countries to make fighters available—all in a prison setting, where the captives had every incentive to make themselves sound like dupes, victims, and henceforth harmless.

The tendency to portray oneself as an innocent has in the past led to ludicrous claims by returnees. They would be laugh-lines if the context were not genocidal. Harry Sarfo, a German returnee from Syria, claimed not to have known what ISIS was, or to have killed anyone during his short stint with the group. A video soon emerged in which he parades with the ISIS ensign and appears to participate in the execution of prisoners. Adult women claim to have been “forced” to travel to Syria. Another ex-fighter says he was injected with a drug that made him think Yezidis—members of a religion whose women have been systematically sexually enslaved by ISIS—were infidels in need of extermination. Needless to say, the pharmacological literature describes no drug with these properties. And the claim of ignorance of ISIS’s true nature is impossible to credit, since press coverage of ISIS’s atrocities has barely ceased during the last three years, and ISIS itself boasts of its crimes in its propaganda.

The respondents in this report do not plead ignorance, but they engage in another predictably exculpatory activity. They claim motivations that make them appear sympathetic and corrigible. They say they wanted a payday—many were jobless in their home countries—and were badly misled about the nature of the work ISIS offered (for a pathetic $50 to $500 per month, according to the report). And they stress humanitarian impulses, chiefly a desire to protect fellow Sunnis from the armies of Bashar al-Assad. When you make your jihad out to be a quest to save babies from a modern-day Herod, it doesn’t sound so bad.

These purported motivations are not necessarily all lies. Shiraz Maher and others have documented the anti-Assad impulse behind the early stages of foreign-fighter migration—especially before the declaration of the Islamic State’s caliphate in mid-2014. But that motivation just happens to be one of the only ones that might lead the jailers of the 43 respondents to conclude that the respondents pose no threat to their home countries, and can be safely released. If you cop to an ideological motivation—“I went to Syria because Islam requires me to fight to defend and expand the caliphate”—you are more or less promising to be violent again. You may as well be begging your government to fit you for a monogrammed orange jumpsuit, and custom-fit manacles, because you will be eating prison food for a very long time.  

The report’s dismissal of the role of religion garnered the most public attention, chiefly due to a woefully uncritical story in The Independent. The UN authors report that only 11 of the 26 people who felt comfortable answering questions about ideology (which the authors identify far too narrowly as “aqidah,” Arabic for creed) said it was “extremely” or “very” important. A majority—16 out of 25—said jihad was “extremely” or “very” important. These seem like significant numbers, given the nonresponse rate, and the incentive to lie. The report, however, downplays jihad and ideology, stating with mystifying certainty that “religious belief seems to have played a minimal role in motivation.”

The nonresponse rate alone probably dooms the report as sound quantitative analysis. But a close reading reveals several other giveaways that the authors, when discussing religious belief, are making assumptions about religion that defy common sense. They confuse duration of piety for depth of piety; religion for religiosity; and, most tellingly, orthodoxy for belief. It appears that for a fighter to be religious, in their view, he should be learned and in broad agreement with a mainstream interpretation of Islam (selected by the authors, I guess), and he should have held that interpretation for a long time, while practicing the piety he preaches.

But that is not how religion works, and it is certainly not how ISIS works. Often, the ISIS foreign fighter is newly pious; he arrives at his piety as a Hemingway character once said he arrived at bankruptcy: slowly, then all at once. He is sometimes inconsistent in his practice. (These very failings, and his own self-hatred over them, are often what drive him into ISIS’s redemptive embrace in the first place.) He isn’t learned—most people are not, including most pious people—and he consciously rejects the mainstream. Rejecting it is not error. It is the point.

Andrew Lebovich explained in a paper for The Brookings Institution last year: “Knowledge of the Shariah is not particularly common for observant Muslims, and it is in many ways a construct of outsiders to think that it should be,” he wrote. “Criticizing the depth of someone’s religious feeling or even knowledge on the basis of their lack of knowledge of Shariah would be like questioning an American’s sense of civic association because they didn’t make their career as a lawyer.” A U.S. Marine can be a patriot, and a fanatical one at that, and not be able to quote a single sentence of the Constitution. If anything, the category of “religion” encompasses so many of the thoughts of foreign fighters (and many normal people) that is too unwieldy a category to be useful in analysis.

None of this means, of course, that the people in this survey were religious. The fact that they left their homes to join an organization that promised them martyrdom and eternal heavenly reward, relentlessly advertised itself as an agent of the Apocalypse, and claimed to be the righteous vengeance of God Himself strongly suggests their religious interests were not casual. That their humanitarian instincts extended only to Muslims—Sunni Muslims—might also count as evidence that they saw the world through religious eyes, making the only relevant division among their fellow humans the one between believer and infidel. (The report calls this “a sense of identity with coreligionists,” and distinguishes it from religion per se. Again, this distinction isn’t clear, unless you think of Islam narrowly as an academic, scholarly, and legalistic activity.)

Finally, there is the telltale matter of what Simon Cottee recently called the report’s “epistemic arrogance.” The authors said that “very few [of the foreign fighters] seemed aware of the conditions and stipulations of Jihad in Islam.” (There’s the expectation of high levels of Shariah expertise again.) “A large number, over 50 per cent, appeared to be religious novices, lacking any basic understanding of the true meaning of Jihad or even the Islamic faith.”

It would be a remarkable UN report indeed that determined “the true meaning of Jihad or even the Islamic faith.” The authors would have better luck explaining the true meaning of Christmas, perhaps to scold me for thinking it is less about the baby Jesus than about watching Bad Santa in my pajamas. Islam is diverse, and jihad a vigorously contested entity within it. ISIS’s interpretation is a minority view—even ISIS acknowledges that—but being in a minority is not the same as being in error, as many other Muslim minorities (Shia, Ahmadis, Deobandis, and Ibadis, to say nothing of Muslim groups not defined by creed) will remind you.

It may seem petty to call the report out for one gratuitous line. But it speaks to the assumptions about religion that get smuggled into reports like this—assumptions that anyone should be able to spot. It doesn’t take much to detect deeper motivation, including religious ones. In my own reporting (which put me in direct conversation with roughly the same number of supporters of ISIS than spoke to the authors of this report, but far fewer who actually made it to Syria), I had to embed myself into their lives when they were not overseen by jailers but free to speak to me however they pleased. I wish I had a larger sample—one that could include more whose beliefs had been tested in the crucible of the land of the caliphate itself.

But less involved questioning, I suspect, will give a harvest of lies, mostly, and virtually no access to the realities and ironies of religious experience. The quantitative survey approach, when limited to a base of 26 jailed respondents, doesn’t teach us much. The job is not done.