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.)