I don't think the film takes itself particularly seriously (I thoroughly enjoyed it by the way) but yes, I do think it has a firmly amoral worldview. It's also playing with film noir tropes. In the classic tradition during the Production Code, the "femme fatale" always had to be punished and crime could not be seen to pay. However, this film (and other modern noirs like The Last Seduction) are more gleefully iconoclastic of such conventions.