But don't they know? God is dead, and with it, his morality!

Well, I think they do know that. That's why these type of New Atheists tend to be so willing to castigate feminists, for example-- they see feminism as the reassertion of a new kind of universalizing morality which has more of a place in religion than in rational society. The same goes for anticapitalist ideas, or anything associated with "the Left". Their view, not mine, obviously.

Unfortunately, this is what happens when you deconstruct the moral framework of society, but have no conception or discourse of how to reconstruct a non-moral, ethical framework. You get reactionaries, atomized individuals, and ultimately the death-spiral of late capitalism and its vacuum of sociality. Nihilism can inform our path out of this hell society, but if nihilism is not accompanied by an understanding of the difference between ethics and morality, and an understanding of the material basis of cultural, then we're just going to see a bunch of entitled fuckers engaging in intellectual masturbation. Movements to transform social conditions have to be...well, social. Not moral, but ethical.