Let us grant the atheist all his premisses. There is no supernatural, divine being as proposed by Christianity or the other great religions. Jesus of Nazareth performed no genuine miracles and did not rise from the dead. Furthermore, religion is a pernicious blight on the world. It is responsible, if not for everything bad in the world, at least most of it. We would all be better off if it simply went away.
Let us grant all that. Yet the facts of religion remain, and in particular I am thinking about the facts of Christianity. Whether it is true or false, the Bible is a fact. The two-thousand year old Catholic Church is a fact. Chartres Cathedral is a fact. Furthermore, the culture inspired by religion is a fact. The Christian-inspired West explored the world, invented modern science, and created Handel's Messiah, Shakespeare's MacBeth, Dante's Divine Comedy, Rembrandt's The Prodigal Son and the Calling of St. Matthew, and the Sistine Chapel.
My point is not that, because Christianity created Chartres Cathedral, the Sistine Chapel, and inspired Handel, Bach, Rembrandt, Dante and Dostoyevsky, that it must be true. It is that these things happened whether Christianity is true or not. There are two possibilities:
1. The Bible and the culture it formed were inspired by God.
2. The Bible and the culture it formed were creative products of the human imagination.
The believing Catholic says the former; an atheist, of whatever stripe, says the latter. But in saying the latter, the atheist doesn't always understand the full implications of his own position. The Catholic attributes the profound achievements of Western culture to natural human creative powers taken to new heights by divine inspiration; the atheist must say that human creative power reached those heights all on its own. In eliminating God, the atheist necessarily elevates the purely human.
And now we come to Nietzsche. If indeed Chartres Cathedral, Dante and Rembrandt are but purely natural products of human imagination, there is nothing stopping us from achieving similar creative heights, albeit without any reference to the divine. The real test for atheism is cultural, and whether it can match the "divinely-inspired" cultural achievements of Christendom with its own cultural achievements that make no reference to God. We know the atheist can mock the cultural achievements of Christendom, e.g. by displaying Crucifixes in urine or smearing paintings of the Virgin Mary with excrement. Nietzsche would be disgusted by such sophomoric atheism. Mockery is the refuge of the immature and the uncreative; an atheist who is satisfied with atheism doesn't need to mock because he is secure in his own cultural achievements. The end result of such mockery is nihilism and, finally, the "Last Man", the denizen of the culture that has given up the attempt to do anything significant and satisfies itself with watching TV from cradle to grave. Sort of like our own.
Desecrating the Eucharist only testifies to the emptiness of contemporary atheism. It is an act that testifies to its own insignificance, for it has power only to the extent that the Eucharist itself is significant. Instead of mocking the Eucharist, the atheist should be creating his own rival, secular liturgies that match the Catholic Mass in sublimity and solemnity. When the atheist sees Catholics reduced to mocking secular liturgies, he will know that he has won.