Thats more the agnostic way of seeing things. Cant prove or diprove a higher being. I identify as an agnostic rather than athiest which take a zero stance on religion.
Well, I'm on the agnostic atheist side of things, so, yes, you can't disprove a god, but saying atheism is a religion is like saying not playing video games is a hobby, since the definition of atheism is a lack of belief in god.
The bottom caption doesn't actually logically follow from the top caption.
Just because a religion might involve the factor of belief without proof, doesn't mean that's the only factor involved. There might be other factors necessary to making something a religion that you'd have to count before being able to conclude logically "therefore, atheism is also a religion."
But it seems safe to say that if the top premise is true, you can logically conclude that therefore atheism is also a "belief."