From SEP:
Atheism and Agnosticism (Stanford Encyclopedia of Philosophy)
"“Atheism” is typically defined in terms of “theism”. Theism, in turn, is best understood as a proposition—something that is either true or false. It is often defined as “the belief that God exists”, but here “belief” means “something believed”. It refers to the propositional content of belief, not to the attitude or psychological state of believing. This is why it makes sense to say that theism is true or false and to argue for or against theism. If, however, “atheism” is defined in terms of theism and theism is the proposition that God exists and not the psychological condition of believing that there is a God, then it follows that atheism is not the absence of the psychological condition of believing that God exists (more on this below). The “a-” in “atheism” must be understood as negation instead of absence, as “not” instead of “without”. Therefore, in philosophy at least, atheism should be construed as the proposition that God does not exist (or, more broadly, the proposition that there are no gods).
This definition has the added virtue of making atheism a direct answer to one of the most important metaphysical questions in philosophy of religion, namely, “Is there a God?” There are only two possible direct answers to this question: “yes”, which is theism, and “no”, which is atheism. Answers like “I don’t know”, “no one knows”, “I don’t care”, “an affirmative answer has never been established”, or “the question is meaningless” are not directanswers to this question."
This is a very clear explanation of why atheism is, indeed, a position. It's not simply a psychological state, it's a metaphysical view that the unvierse is absent gods, opposed to theism being 1+ existing god. Further, atheism doesn't exist in a vaccuum. The second you get to morality, epistemology, materialism, and so on the more defense the position needs.
In no other cases do we accept a position that does not need defense and support, so why do some do so with atheism? Even worse, why not just defend your atheism if you can?
A great example is being told "you don't need to defend/support being an abigfootist." That's ... That's not true. If you think Bigfoot is fiction you need reason to think so or we shouldn't seriously consider your position. For instance - "I don't believe because the video evidence was shown to be a man in a monkey suit". That's a reason one can defend for holding their position. If you disagree, please share other positions outside of atheism that one can accept without reasons or evidence. Can anyone claim any position for any reason and it should be accepted, or is it special pleading?
Why do I think atheism has taken to this? Burden of proof games. The idea that any position can be accepted without needing to support it is absurd and dangerous. There is no "burden of proof," anyone who has a position needs to defend it. Ask yourself: if you don't have evidence and arguments to believe something, and can't / aren't willing to defend it... Is it really a worthwhile position?
