The religious have done a remarkable job of convincing themselves of their generosity of spirit. Try as I may to give my rhetorical adversaries the benefit of the doubt, I see all forms of supernatural religion as suspect on this count. Anthropomorphic gods are narcissistic projections. Incorporeal gods are immaterial abstractions. Impersonal gods are obscurantist metaphors. Religion is characterized by that unconditional allegiance to custom that we accuse the doctrinaire of imitating when we make analogies between religion and non-supernatural dogma. Religious mendacity of spirit extends to the intellectual (LOGOS), emotional (PATHOS) and moral (ETHOS) spheres of human experience.
Naturalism, unlike religion, is based on what we can observe. Some religious--and even post-modernists--would have us view naturalism as a dogma on par with religion. The problem is that science and religion are irreconcilable and cannot be embraced on equal terms without inviting cognitive dissonance. We know, for example, that sentience is a function of evolved biological complexity. This fact is incompatible with the notion of an eternal, incorporeal consciousness. The intellectual mendacity of religion insists on a narcissistic understanding of a universe created for us in which our consciousness is eternal.
It has been said by innumerable sages that faith is a form of willful self-deception. Faith is only invoked in defense of an untenable proposition. The siege mentality of the religious betrays their underlying sense of entitlement. Before accusing atheists of excessive stridency, it would be sensible to consider the fact that the customary religious exemption from scrutiny is culturally conditioned. It is a vestige of religious privilege that has been used to persecute heretics since time immemorial. Blasphemy is a victimless crime, yet it is punishable by death in certain parts of the world and by marginalization in others.
Religious mendacity of spirit also takes the form of emotional dependence. This emotional dependence is especially pronounced in monotheistic religions, but it is also observed in non-theistic religions with some form of karmic enforcement of religious pronouncements. Even personal superstitious rituals or seemingly innocuous statements such as "everything happens for a reason" suggest a determination to reject the disconcerting notion that we live in an indifferent cosmos. Belief in divine intervention is analogous to low-grade Obsessive-Compulsive Disorder.
Emotional dependence induced by religion reflects a mendacity of spirit to the extent that it represents humans as fundamentally unworthy of divine favor and ungrateful in lamenting adversity. To hold oneself to such a standard without judging others by it is to invite cognitive dissonance. It is a fundamentally intolerant doctrine. It is a short distance between judging non-believers unworthy of divine favor and reveling in their misfortunes. Religious conformity often reads as calm resignation, but it can be rallied for righteous indignation at a moment's notice.
The ethical mendacity of religion can be observed in the insistence on attributing morality to religion. Even religious moderates who choose their religious observances cafeteria style will attribute their virtue to their religious heritage. Biblical authority is a notoriously unreliable source of compassionate moral precepts, yet the doctrine of diving revelation remains intact. What is missing is the acknowledgement that empathy is hard-wired into human nature. Persons deemed pathologically lacking in empathy are the exceptions that prove the rule. Those who take orders from invisible beings are considered either prophets or psychotics, depending on the context.
The religious who claim to base their personal morality on religion yet insist that they do not judge non-believers are making a disingenuous claim. It is psychologically impossible to understand religion as inherently virtuous without judging the non-believer as somehow deficient. To minimize cognitive dissonance, believers will have to acknowledge their empathy as an inherent human quality nurtured by opportunities to engage in moral reasoning. These opportunities may be provided by religious culture but could be nurtured in a secular context if religion did not crowd out other opportunities.
Religion inculcates a mendacity of spirit in the intellectual, emotional and moral spheres of human experience. This is not to say that the religious cannot obtain generosity of spirit, but they do so in spite of supernatural belief, not because of it. Intellectual curiosity, emotional autonomy and moral reasoning are the benchmarks of adulthood and the casualties of religion.