A summary reading of the history of myths teaches us how religious even the most atheist of us remains; how the religious lives on in us, in our imagination, ideas, impulses, emotions, motives, narratives of life, etc., irrespectively of what our rational mind believes. We remain worshipers in a temple we no longer believe in its existence. We remain idolators of a power in which we ceased to believe, at the very thought of which we cannot hold our laughter, our cynicism — and what is cynicism if not the pain of a wound? We may know a lot more, we moderns, but we feel a lot less and less profoundly, and the world of our feeling, intuition, and imagination has shrunk in proportion to the horizons which our minds have widened. We know no reverence; we are deeply irreverent. The sacred has been expunged from our rational world, and that is a direct correlation with the way we are handling our planet and ourselves.
The ascetic moralism of religion regarding sex tends to sever it from the sphere of emotions. Sexuality, being repressed, the need for it does not go away, but suffers a degradation and acquires, when it surfaces, an urgency and paroxysm. Much of the modern liberalism in sexuality is precisely such an urgency and paroxysm that does not recognize its origin, is a prolongation of the rift at the heart of the human soul between sexuality and emotion. A man still fighting a ghost who is no longer here.
The morality of religions that stigmatizes certain acts (or ideas of acts) as sin, obstructs the ability of reason to comprehend the dynamics (emotional, social, biologic, etc.) that are affecting the acts and thus hinders any possibility for true understanding and change.