A recurring theme in my discussions with secular humanist centers on the subject of morality. First a illuminating part of the Oxford definition:
6.b. Theol. The property of certain enactments of the Mosaic Law by which they belong to the moral (as opposed to ceremonial, etc.) law and therefore retain their validity under the Christian dispensation. Cf. MORAL a. 5a. Obs.
This leads me to the crux of my argument. The secular humanist generally does not believe in God. They also disagree with the influence of religion on society and government. Now, arguing from the perspective of social evolution, and not from faith, one can make the point that the establishment of morals is inextricably linked to religious behavior. The development of modern Western society is fundamentally linked to the Christian church, and before that the Mosaic Law. Now, other societies exist, with moral behavior, and codes of ethics. Conversely, the existence of a secular society that was formed without the influence of religion is a remote hope. I would contend that it, like the experiment of pure communism, would fail miserably. And my reasoning would not rely on faith. I would argue that we are genetically predisposed to succeed in a religious framework. And that the greater organism which is society, evolves in the context of communities who's members organize in the context of religion.
Its social Darwinism with a twist. Its God as the designer of evolution. Furthermore, my personal views on this subject would label me a heretic, get me excommunicated, and burned at the stake (or boiled in oil), as well as scoffed at by peers, thrown in jail in Cuba, get beheaded in Saudi Arabia, among various other punishments. For me, religion is the biblical meaning, "true religion is taking care of widows and orphans", and not the crystallized structures of denominations, the ridiculous fiction of Dante and Milton, or whatever other social control and fantasy you derive from these. What an amazing system life is. And how would you make it better?