An Agnostic requires proof before converting to either atheism or theism. An Atheist needs no proof, they simply "know" that a deity does not exist.
I do not know that a deity does not exist, and I am an atheist. I lack the belief that deities exist, which is what makes one an atheist. Why? Because theists have made a claim, many times, and always failed to deliver evidence supporting their claim. This has happened so very much, in the entire spectrum of deities proported to exist, that I find the chance of any of them existing when the claims of their existance have uniformly failed to be unlikely in the extreme.
Burden of proof is on the person making the claim, and Atheists claim there is no deity - with no possible way to prove it.
Your problem is that the default postion of any individual is implicit atheism (not ever knowing of the idea of deities, as opposed to explicit atheism, which would be like me.). They can grow, live, and die without any contact with these ideas, and as such it is the default position. To sway someone from the default postion in a rational manner, you need evidence. When a theist confronts an implict atheist with their ideas, one of two things can happen:
A. The implicit atheist can believe them despite the lack of evidence, and has now made a consious choice on the subject, becoming a theist.
B. The implicit atheist can reject their claim, and now has made a consious choice on the subject, becoming an explict atheist.
Atheism is a rejection of Theism. Without Theism, Atheism would be meaningless - everyone would be irreligious rather than Atheist.
Everyone would be an implicit atheist, which is indeed a irreligious position.
Trying to define Atheism's relevance by using arguments based on stupid made up religions or things that nobody (or almost nobody) believes in is absurd.
Sure it is. I was drawing a parallel to show you the meaninglessness of the "It has followers, and is therefore more important to the subject." claim.
If you want to discuss the relevance of Atheism, discuss it in a relevant way - in the context of real religions.
Done.
I deny that rabid invisible ghost rats are trying to eat my feet the Abrahamic god is going to send me to Hell for disbelieving in it. Am I being irrational? I can sense no rabid invisible ghost rats god, nor is any effect claimed of the rat's god's actions observed. There's no reason to believe in the deadly, deadly ghost rats hateful, self-rightious god that could be skittering around you judging your soul at this very moment, so why would the burden of proof be on the person denying the existance of the unspeakable ethreal vermin? unspeakable ethreal god?