No, but it's what I would pick on a form in the "religion" spot if I had to.
Agnosticism isn't a religion. Atheism is. You have to have faith to "know" something doesn't exist with certainty.
Atheists aren't claiming to have positive proof of the nonexistence of God.
The term means that someone has not seen convincing evidence for God's existence.
Likewise, I wouldn't say I'm agnostic about Russel's Teapot or any mythical idea because that terms tends to imply that you find the existence and nonexistence of the thing to be comparably likely.
Agnosticism is the view or belief that the existence of God, of the divine or the supernatural is unknown or unknowable.
Atheism is an absence of belief in the existence of deities.
Your definition of atheism is not my experience with pretty much every atheist I've ever met. It's not absense of belief, but belief that God doesn't exist. There was never anything nuanced about the definition.
Now we can say absense of belief for the sake of discussion, but then it becomes an issue of semantics, as there is overlap with agnosticism. But it doesn't match my experience at all. Most atheists will call you names for suggesting anything but the idea that the laws of physics are a complete description of reality. Teenage edgelords mainly.
There's a difference between speaking of a category of behavior and being personally named.
No Satanism, Pastafarianism or Wiccan on the list? >:(
Considering sports and religion always go out of control with large crowds, I bet the Quidditch matches would end up in massacres too frequently
Isn't that what basically happens when you're born? I seriously wonder how many Christians would be such if they were born in India or China.
Not a single new age woo woo occult religion in the bunch. There are dozens of us!