All literature is just literature, behind all authority is mere authorship. To quote NWA, "an AK-47 is a tool"; a book, also, is a tool. 君子不器。
The implicit tension here is that most (21st century) atheists want to avoid making a strong claim that god does not exist; instead, they merely want to argue that there is insufficient evidence of god's existence. This has created the absurd assumption (commonly referred to as if it were an irrefutable truth) that all atheism is merely agnostic atheism, i.e., as if it were impossible to have definite knowledge (gnosis) that the arguments in favor of the existence of a god (or gods) are false.
The shift in argumentation here (from atheist-vs.-agnostic to nihilist-vs.-atheist) is significant, although subtle: I am not talking about the existence of god, but instead the existence of literature, the existence of mythology, and then the question of what attitude we should have toward this literature (these myths) and their authors. That is the only valid question from a nihilist's perspective: there is nothing to be believed in, there is nothing to prove the non-existence of.
In parallel: it would be absurd to invent an agnostic-vs.-atheist dispute over the existence of Tom Sawyer and Huckleberry Finn ("can you really prove that Tom Sawyer wasn't an actual person, who actually existed, or are you merely arguing that there's insufficient evidence to compel us to believe in him?"). Nobody should even ask the question, "Given the impossibility of gnosis, how do you deal with the problem of the existence or non-existence of Huckleberry Finn?"
There may nevertheless be legitimate questions of, "Is this good fiction?" if we can first establish that we are discussing fiction as fiction, removing "proof of existence" from the equation entirely. Is this actually a good story to teach to children? What were the intentions of the author in writing this story, perhaps in contrast to the significance that is now commonly ascribed to it? Both for religious texts and for Tom Sawyer, Batman, etc., these questions have to be asked (nihilistically) both with a view to the creation and destruction of culture within any given century. Are people just going to continue reading Tom Sawyer to their children forever and ever? What is going to change? How is it going to change? Who is going to change it?
In this way, obviously, nihilism is more revolutionary than atheism: it doesn't merely debate abstract questions on call-in talk shows, but actually endeavors to change the world.