Here are two (politically motivated but opposing) Christian arguments about if atheism is a religion or not.
The first argues that atheism is not a religion because it is not theistic. The purpose of this argument is to deny atheists any protection under the First Amendment.
It is not uncommon for philosophers and social commentators to refer to any overarching belief system as a religion. For example, just out from Daniel Mahoney is The Idol of Our Age: How the Religion of Humanity Subverts Christianity (2018), in which he argues that secular humanism is treated as ultimate truth by many and, in that sense, becomes a “religion” in competition with Christianity.
The evidence is overwhelming, however, that religion, as originally understood by both the public and the framers as used in the First Amendment, did not include atheism…
The Constitution is, of course, a legal document, and the common, legal usage of terms when it was adopted are highly persuasive evidence. Blackstone’s Commentaries, published in the 1770’s and widely in use in the colonies, has an entire chapter entitled “Of Offenses Against God and Religion.” Foremost among those are laws forbidding atheism and other non-theistic heresies. Religion was understood to be inextricably linked to theism. Similarly, Noah Webster’s first compilation of American English in 1823 defined religion as involving the worship of God (and modern dictionaries in their listings do the same as the most common definition).
There is further proof from the drafting history of the Religion Clauses, as the framers during the debates rejected a formulation that would have expanded protections to atheists. Madison originally proposed that “freedom of conscience” be included in the Bill of Rights, but others objected that such a provision would endanger true, theistic religion and protect atheists. Madison’s broader language protecting conscience was passed by the House, but it was rejected by the Senate and by the conference committee and so never found its way into the Bill of Rights. Is Atheism Religion Under the First Amendment’s Religion Clauses?
The purpose of the next argument is to suggest that atheism is a religion so that it will be subject to the same restrictions that theistic religions are subject to under the First Amendment.
Religion is a difficult thing to define. Various definitions have been proposed, many of which emphasize a belief in the supernatural. But such definitions break down on closer inspection for several reasons. They fail to deal with religions which worship non-supernatural things…
A better way to determine whether a worldview is a religion is to look for certain characteristics that religions have in common. The framework set forth by Ninian Smart, commonly known as the Seven Dimensions of Religion, is widely accepted by anthropologists and researchers of religion as broadly covering the various aspects of religion, without focusing on things unique to specific religions.
The seven dimensions proposed by Smart are narrative, experiential, social, ethical, doctrinal, ritual and material. Not every religion has every dimension, nor are they all equally important within an individual religion.
Atheists often claim that their belief is not a religion. This allows them to propagate their beliefs in settings where other religions are banned, but this should not be so.
Atheism shouldn’t be taught or enforced in settings where other religions are banned and shouldn’t be favoured by laws which imply a religiously neutral government.
Is Atheism a religion?
These two articles are an example of the political forces behind the question “Is atheism a religion?”