Actually, the subtitular sentence is ambiguous. The thought is that at least one leftist understands that religion has far deeper roots in human nature than a typical leftist analysis can expose, let alone eradicate. The leftist in question writes,
The left has always had difficulty recognizing the power of religion. Aren’t all religions the ideological tools of the ruling class? And aren’t all millenialist and messianic uprisings the ideologically distorted response of subaltern groups to material oppression? Religious zealotry is a superstructural phenomenon and can only be explained by reference to the economic base. These ancient convictions are particularly obfuscating today. Parvez Ahmed, a Florida professor who is fully cognizant of the “scourge” of Boko Haram, provides a typical example in a recent blog [sic]. He argues that “much of the violence [committed] in the name of Islam is less motivated by faith and more so by poverty and desperation.” Similarly, Kathleen Cavanaugh from the National University of Ireland, writing on the Dissent website, insists that “the violent and oppressive actions [of ISIS] have little to do with religion per se,” but rather are “underpinned” by material interests. But is this right? Why don’t poverty, desperation, and material interests produce a leftist rather than an Islamist mobilization? In fact, the religious revival, not only among Muslims but around the world, among Jews and Christians, Hindus and Buddhists, has enlisted supporters from all social classes, and the driving motive of revivalist activity seems, incredibly, to be religious faith (Fawaz Gerges’s Journey of the Jihadist: Inside Muslim Militancy provides ample evidence of religion’s power).
(Michael Walzer, "Islamism and the Left," Dissent 62 [winter 2015]: 107-17, at 112-3 [brackets in original])
Although Walzer has a better understanding of human nature than most lefties, he betrays his residual leftism by his use of 'incredibly' in the last sentence above.
Why is it "incredible" that people should have religious faith? Only a benighted leftist, bereft of understanding of human nature, could think that human beings could be satisfied by a merely material life. Religion answers to real needs of real people, the need for existential meaning, for example. Some meaning can be supplied by non-exploitative, mutually beneficial social interaction. But not ultimate meaning, meaning in the face of death. To put it cryptically, an "existing individual" (Kierkegaard) standing alone before God and eternity is no Marxian Gattungswesen.
Whether any extant religion can in fact supply ultimate needs for sense and purpose and transcendence is of course a very different question. Suppose that no extant religion can. It would be a mistake to conclude that the needs are not real. It would be even more of a mistake to conclude that something as paltry as the utopias envisaged by Marxists could satisfy religious needs. Supplying everyone with an abundance of natural goodies will never sate the human spirit. But it takes spirit to understand this point.
Leftists, and atheists generally, typically have a cartoon-like (mis)understanding of religion.
No higher religion is about providing natural goodies by supernatural means, goodies that cannot be had by natural means. Talk of pie-in-the-sky is but a cartoonish misrepresentation by those materialists who can think only in material terms and believe only in what they can hold in their hands. A religion such as Christianity promises a way out of the unsatisfactory predicament in which we find ourselves in this life. What makes our situation unsatisfactory is not merely our physical and mental weakness and the shortness of our lives. It is primarily our moral defects that make our lives in this world miserable.
We lie and slander, steal and cheat, rape and murder. We are ungrateful for what we have and filled with inordinate desire for what we don't have and wouldn't satisfy us even if we had it. We are avaricious, gluttonous, proud, boastful and self-deceived. It is not just that our wills are weak; our wills are perverse. It is not just that our hearts are cold; our hearts are foul. You say none of this applies to you? Very well, you will end up the victim of those to whom these predicates do apply. And then your misery will be, not the misery of the evil-doer, but the misery of the victim and the slave. You may find yourself forlorn and forsaken in a concentration camp. Suffering you can bear, but not meaningless suffering, not injustice and absurdity.
Whether or not the higher religions can deliver what they promise, what they promise first and foremost is deliverance from ignorance and delusion, salvation from meaninglessness and moral evil. No physical technology and no socio-political restructuring can do what religion tries to do. Suppose a technology is developed that actually reverses the processes of aging and keeps us all alive indefinitely. This is pure fantasy, of course, given the manifold contingencies of the world (nuclear and biological warfare, terrorism, natural disasters, etc.); but just suppose. Our spiritual and moral predicament would remain as deeply fouled-up as it has always been and religion would remain in business.
It helps to study history. The Communists slaughtered 100 million 'cows' in the 20th century alone. But where's the beef?
It could be like this. All religions are false; none can deliver what they promise. Naturalism is true: reality is exhausted by the space-time system. You are not unreasonable if you believe this. But I say you are unreasonable if you think that technologies derived from the sciences of nature can deliver what religions have promised, or any socio-political re-arrangement can.
As long as there are human beings there will be religion. The only way I can imagine religion withering away is if humanity allows itself to be gradually replaced by soulless robots. But in that case it will not be that the promises of religion are fulfilled by science; it would be that no one would be around having religious needs.