I read a former-atheist article yesterday which interested me greatly. The author described a-theists as wanting to argue against God, in the desperate hope that they can prove He doesn't exist. Then they can do whatever they want and not feel bad about it, or so they hope.
Only she said it doesn't actually work that way, instead, there is the elephant in the corner lurking all the time. A niggling unrest in the spirit, a knowledge that there is more to life than 'nothing'.
Another article read that atheists are usually angry at God on a personal level. Perhaps something in their life happened that "shouldn't have", or wasn't fair, or hurt very badly, and God is to blame. So they shake the fist in anger and say "He doesn't exist".
A different author said he sees it as God doesn't give up on the atheist and continues to give little reminders that He is always there, whether they like it or not. And they don't like it because they feel uncomfortable, a bit like having a light shone into the darkest dirtiest parts of our house that you're not proud of and would rather hide from.
All of these authors shared the same view that atheists spending a lot of time arguing against God is ironic, because most of us don't believe in Father Christmas but also don't rage against people who do (or who indoctrinate their children to try and persuade them that he is true!), but that God is treated differently because there is no one like Him.
Perhaps when an artist is most unsettled and uncomfortable they will take issue with Christians or the bible, or public worship and prayer. But underneath it all is their argument with God himself, for whatever their personal reason for that.