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.
Atheism isn't a religion.
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.