The behavior of humans around the world prior to our present awareness in the U.S. that the Creator endowed every human being with certain inalienable rights included such things as genocide, killing, cannibalism, rape, slavery - all kinds of brutality much like predator animal species, i.e. kill or be killed, survival of the fittest, unconstrained lust.
A true atheist/agnostic would say that all this killing was a good thing, evolution at work - the clever, strong, industrious and skillful got rid of the weaker humans thus improving the gene pool. Indeed, he would say the genetically inferior should be killed in the womb or in infancy and if already matured then sterilized to prosper the gene pool. Eugenics or infanticide (e.g. Singer) follows from that worldview.
But many who call themselves atheist or agnostic are actually anti-God or anti-Christ and instead seek to set themselves up as the measure of what is right and what is wrong seeing themselves as superior, i.e. "god" like.
Should they succeed in gaining political power, the prognosis is bleak. Death by government was much higher in countries which were officially atheistic and when colonizing governments officially viewed the inhabits as less valuable than themselves.
Alternatively in the present age of political correctness, such a government may view the rights of animals as equal to that of humans because there can be no qualitative difference in a PC intellectually atheistic/agnostic worldview (e.g. Singer.)
Where "man is the measure," this is the result we can expect — if history is any guide.
With God out of the picture — with truth and justice out of the picture — all that is left is the dynamic of power. The endgame is the "war of all against all," a lapse into the ideology of "the survival of the fittest."
Note: that's the "fittest"; not the "best." The laser-like focus on the physical eclipses all moral criteria.
Thus man ceases to be man, and finally becomes a "mere" animal....
And when man becomes an animal, he does not opt to be a dove. Rather he becomes a vicious beast, and the natural (and social) world becomes a spectacle of "Nature, red in tooth and claw," to quote Charles Darwin. Some folks evidently find this scenario appealing in some way. I do not for the life of me understand why.
Dearest sister in Christ, sometimes I wonder whether the human race has bifurcated into two camps: Those who are desperately trying to preserve their true (that is God-given) humanity in a chaotic world, and those who are trying to throw it away with both hands, thus further fanning the flames of chaos....
But the fact is the latter have reduced the universe to the size and competence of their mental operations. Surely, the world is "bigger" than that!
Thank you ever so much, dearest sister in Christ, for your most eloquent essay/post!