"Atheism" is "A - theism". It's a negation of "god".

Consequently, it relies on a culturally biased, unnecessary and ill-defined concept of "god". It's not just culturally biased by being a rejection of the Christian god. It's culturally biased by being a rejection of the wide diversity of deities in human cultures. Atheists fall victim to the intellectual pitfall of relying on already-existing ideas in the unreliable library of human understanding. It misses the philosophical ideal of attempting to articulate the nature of reality purely and directly.

At best, atheism is incomplete, particular and does not constitute a fully formed worldview. At worst, it is a pathological distraction from genuine philosophical problems. If an articulate person is asked to define "god", the descriptive power of the word is invariably drowned and killed by more meaningful ideas.