Atheism as a religion

If atheism is a religion, then bald is a hair color.

Atheism as a religion is the idea that atheism is just another religion, and not the absence of one. Advocates of this idea often mix it in with other ideas about secular "religions" (such as liberalism, agnosticism, and environmentalism) being religions. The concept of atheism-as-a-religion is separate from the atheist "churches" such as the Sunday Assembly. This is often considered a point refuted a thousand times. It is also separate from the fact that some atheists may legitimately participate in some religions (such as Confucianism, Hinduism, Buddhism, and Unitarian Universalism), as well as illegitimately form part of some (as with some clergy in the  Church of England).

Arguments about atheism being a religion
Arguments against the religious nature of atheism tend to make evident that atheism has no creed, and is just a group of people with a shared disbelief in all the gods. As atheism is being defined as a lack of something, many people just consider it the state of there being no religion. Atheism would be better considered the lack of something. This argument could lead to agnosticism being a religion, but agnostics do not believe certainly in any religion, so also should not be considered to have a religion.

Definitions of a religion from various sources generally read in such a way to preclude atheism from consideration.

2: a personal set or institutionalized system of religious attitudes, beliefs, and practices… 4: a cause, principle, or system of beliefs held to with ardor and faith

Atheism lacks multiple beliefs as in the second definition (definitions 1 and 3 are irrelevant). Atheism precludes faith from reasoning, and as such can not be held to with faith. Ergo, those definitions makes clear that atheism is not a religion.

Indeed, the etymology of the word atheism comes from the Greek atheos (αθεός), meaning without god(s).

Atheism functioning as a religion
Atheism is a religion like how Ken Ham is a scientist

Atheism is sometimes considered a religion option on surveys and in the resulting graphs that are products of those. Certain atheist organisations such as American Atheists contain some of the trappings of a religion, such as a symbol, a website, and sometimes meetings of believers in such organisations as Skepticon. There are also atheistic “churches” such as Sunday Assembly, and religions where many of the attendees do not believe in God, such as Unitarian Universalism. These can be considered the religious form of atheism, as opposed to normal atheism that does not require any ritual. The most radical atheists, such as some New Atheism-affiliated people, tend to encourage or tolerate proselytizing of atheism, making atheism more like a religion.

Considering atheism a religion
Many of the people who believe that atheism is a religion are conservative Christians who find that they cannot understand how others lack faith, and so just presume that it is in fact a religion. This is also often done when it is politically expedient, framing atheism as a religion so that it can be disconnected from its base in a lack of support of faith from other realms of knowledge besides religion. Some forms of Confucianism and Buddhism also lack any gods. Almost any blogging site or social media platform with any conservative presence at all will eventually have a few people claiming that atheism is a religion because of their view of the divide between science and religion. Quora has quite a few conservative writers claiming that atheism is a religion, sometimes in conjunction with liberalism. . Atheists Outline Their Global Religious Agenda is a notable example of a creationist, Ken Ham, claiming that atheism is a religion of sorts.