Worldview is a broad term and everyone has one.
To put something that is complicated simply, a worldview is how one views the world.
Therefore atheism is a worldview in that the atheist views the world as being absent of God or gods.
This belief alone, regardless of any logical gymnastics the post-modern atheist is engaged in these days, makes atheism a worldview. An objective analysis of the shared beliefs which flows from that basic assumption becomes even more telling.
For example, the statement “I won’t believe something for which there is no evidence.” Is a common statement. If one digs a little deeper one discovers that the evidence must be empirical in nature thus barring any rational deductive or inductive reasoning one might draw or infer from observing the material and immaterial aspects of reality . This commitment to materialism and naturalism is likewise a common value held for those in this worldview.
There are hundreds of other common values and shared paradigms that one commits to by adhering to this worldview.
Therefore it is neither honest nor intelligent to say that atheism is not a worldview. Or at the very least a defining feature of one.
Additionally to ignore the history and the development of atheism philosophically across time is also a feature of this post-modern era.
All human thought has a traceable history in which those paradigms are developed and built upon.
It is therefore incoherent of the post-modern atheist to ignore the development of this school of thought across time.
It is not surprising of course to find that a post-modern expression of atheism is attempting to ignore the development of thought across time since radical subjectivism and the disillusionment of truth propositions is a common feature of virutually all post-modern schools of thought.
It is therefore reasonable to conclude that this expression of atheism and its incoherence can be classified as post-modern atheism
As opposed to Modern atheism, neo-atheism, Marxist-Leninist atheism, classical atheism, rational atheism, and ancient atheism.
All of these categories are legitimate categories of atheism since the ideas proposed by people who identified as atheist across time and how they defined their atheism is distinct from one another in novel and identifiable ways.