Look and See
In a public debate, those with the facts are at a serious disadvantage because their listeners have to learn something in order to understand arguments supported by evidence. Inertia favors appeals based on platitudes and commonplaces since these notions are already well known and people tend to think that ideas are true simply because they are familiar. In debates about religion, for example, it is taken as a given that belief in the supernatural promotes morality and prevents social breakdown while even a cursory examination of the historical record suggests that things are far more complex. Sometimes religious institutions have maintained order in the aftermath of military defeat and general demoralization as when the bishops of Western Europe, often members of the senatorial class, stepped in to manage as best they could the ruined provinces of a fallen empire. In these instances, as perhaps in the case of some of the successor states of the USSR, religion was important by default. On the other hand, where societies are doing well, as in contemporary Scandinavia, or manage to organize themselves around nationalism or secular ideologies, religion is often largely irrelevant. And there are also cases such as Mongolia and Tibet where a mania for religion appears to have led to national decadence. Historical sociology does not yield simple conclusions, which is not to say that it doesn’t yield any conclusions at all. The point is, you have to look and see.
By the way, the atheists are as fond of coarse answers as any believer. Every time I encounter some villager waving the bloody shirt of the Crusades or the Inquisition, I find myself wondering if any of these worthies has bothered to assess the historical record. As a cause of mortality, getting burnt at the stake is pretty insignificant compared to brain tumors or probably even lightening, not to mention really serious killers like spousal jealousy. Similarly, though there have certainly been times of terrible religious wars, there have also been long eras during which people found other reasons to kill one another. It is trivially true that every kind of villainy correlates with religiosity; but that just reflects the fact that a proclivity to superstition and fanaticism, if not part of the essence of humanity, is at least a universal accident like original sin. Indeed, on balance, it may have been a good thing that organized churches have managed and channeled our potentially dangerous spiritual impulses over the centuries. Thus even the Spanish Inquisition, terrifying as it undoubtedly was, did serve to curb the homicidal prejudices of the Spanish people, for whom being a Christian had become a matter of blood, not belief, If you think Torquemada was bad, wait until you face a Castilian mob.