I get the analogy, but it doesn’t quite hold up. Choosing not to collect stamps doesn’t shape how you view morality, human dignity, or the meaning of life. But denying the existence of God does touch all those things. Atheism might begin as a lack of belief, but when that lack becomes the foundation of your view of reality, it functions as a worldview whether it claims to or not.
Once you remove God, you're left with big questions: What grounds morality? What gives life value? What defines right and wrong? You must answer those somehow, and the way you do it forms a worldview. That’s why many atheists gravitate toward naturalism, humanism, or moral relativism. Not all answer these questions the same way, but they can't avoid answering them.
So while atheism might not prescribe a worldview, it inevitably shapes one. And when it’s the organising principle of a political regime, as it was in Stalin’s USSR or Mao’s China, it becomes much more than a personal belief. It becomes a framework for power, ethics, and human worth, and history shows the consequences of getting those answers wrong.