I feel like this idea of atheist humanism (opposed to Christian Humanism) bears out what I have already said elsewhere.
Mainly, that if we are all an accident, without purpose or meaning, it is hard to see a good reason for ethics to matter.
For what would you base it on besides practical cooperation? And then what about all the people that refuse to be practical in this way? You can’t call them evil. I mean, you don’t even have the language for it.
And with no ethics, might makes right…to our eventual horror.
That breaking with Transcendent Being began with “a reversion to paganism,” but ultimately “came to a head in the most daring and destructive form of modern atheism: absolute humanism, which claims to be the only genuine kind and inevitably regards a Christian humanism as absurd.” And so arose “atheist humanism (l’humanisme athée), which sought to protect and extend human greatness by emancipating it from bondage to God. But this, de Lubac argued, ended by unleashing bestiality and evil. The Nazis were the logical culmination of the attempt to construct humanism without God. The proper response to the Nazis therefore required not just fighting them but also re-emphasizing the imago Dei, for otherwise the Nazis’ opponents could become all too much like them.
-Alan Jacobs, The Year Of Our Lord 1943 (Amazon)