Was there ever a greater atheist than Nietzsche? Not in my mind. Woe to the sophomoric Facebook atheists who have not come to grips with their new shepherd. They are the "village atheists" Nietzsche so vehemently derides.
What is their problem? It is (especially for the so-called "deconverted atheists") that they thoughtlessly retain certain core beliefs intrinsic to the Christian theistic worldview, co-opting them into their "atheism." This is, for Nietzsche, a category mistake of the first magnitude.
Consider, for example, the Facebook atheist's outrage at the supposed evils of religion. In their moralistic protesting they function as Christians in atheistic disguise, for the righteous moralism that fills their being is precisely core to Christianity.
As Nietzsche knew, real atheism abandons such moral beliefs as it launches into its nihilistic ocean. Terry Eagelton explains:
"Nietzsche sees that civilisation is in the process of ditching divinity while still clinging to religious values, and that this egregious act of bad faith must not go uncontested. You cannot kick away the foundations and expect the building still to stand. The death of God, he argues in The Joyful Wisdom, is the most momentous event of human history, yet men and women are behaving as though it were no more than a minor readjustment...
in Nietzsche's view it does not follow either that we can dispense with divine authority and continue to conduct our moral business as usual. Our conceptions of truth, virtue, identity and autonomy, our sense of history as shapely and coherent, all have deep-seated theological roots. It is idle to imagine that they could be torn from these origins and remain intact." (Eagleton, Terry. Culture and the Death of God, p. 156)