The American Atheists say that “Atheism is one thing: A lack of belief in gods…Atheism is not an affirmative belief that there is no god nor does it answer any other question about what a person believes. It is simply a rejection of the assertion that there are gods. Atheism is too often defined incorrectly as a belief system. To be clear: Atheism is not a disbelief in gods or a denial of gods; it is a lack of belief in gods…”
“…Atheism is not a belief system nor is it a religion.”
In describing the difference between an Agnostic and an Atheist, notice how they describe atheism: “…Agnostic isn’t just a “weaker” version of being an atheist. It answers a different question. Atheism is about what you believe. Agnosticism is about what you know.”
Let’s repeat that “Atheism is about what you believe.”
So by their own words, atheists “lack a belief in gods” and “atheism is not a belief system”, but they are distinct because of their beliefs…so by their own words, atheism is a belief system…right? Because Atheism is about what they believe.
They don’t exactly just “lack a belief in gods” they actually have an affirmative belief (or trust) that based on the evidence there probably is no god or gods.
To put it another way, atheists are now on par with other religious belief systems in the sense that they all hold beliefs.
Likely most atheists would agree that they believe that based on the evidence, 2 + 2 = 4, that based on experience (evidence), the water they drink usually won’t kill them, and that based on the evidence, they believe that there is probably no god or gods.
Try that with an atheist friend. Ask them “Is this a true statement? – Based on the evidence, you believe (or trust) that there is probably no god or gods.” And then you can point out (kindly with grace) that they do hold an affirmative belief.
Those were all affirmative belief statements. It is impossible to live without affirmative belief statements. That means – “we all believe something.”
The question then becomes “whose beliefs match the evidence and fit reality the best?”
…And that’s where Christianity shines! – Don’t believe me? – Then go do the research!
Source: What is Atheism?, American Atheists, https://www.atheists.org/activism/resources/about-atheism/, accessed March 29, 2022.