Religion is defined as: "a set of beliefs concerning the cause, nature, and purpose of the universe". So, you're right, to a point, but then that makes evolution a religion. Since I'd have to estimate 99% or so of athiests are evolutionists, it's really just become a synonym, of sorts.
I hope this doesn't sound rude, because it's absolutely not meant to be: The argument you used really just seems like a way to say "I'm different" while not being different.
FYI, I am an athiest, also. More on that, later.