I went the other way. Used to be an atheist, then gave it some more thought and then became an agnostic. Atheism is clearly a religion, IMO.
I examined it this way and my thinking is this...First, two definitions of agnosticism...""a person who holds that the existence of the ultimate cause, as god, and the essential nature of things are unknown and unknowable, or that human knowledge is limited to experience.""
""Agnosticism is the view that the truth value of certain claims—especially claims about the existence or non-existence of any deity, but also other religious and metaphysical claims—is unknown or unknowable.""
I submit to you that we can't know if there is a deity. Until you get in a spaceship and explore the entire known universe searching for a supreme deity, then you can't know if there is one or not. If you do this search, then return to earth and pronounce that there is no deity to be found, then I will become an atheist. Until then, agnosticism is the proper way to think. Without doing this search while proclaiming atheism, clearly turns it into a religious belief. You have to admit you can't know if you don't do a search. And with such a very structurally complex place such as the universe, you can't outright dismiss the work of some unknown deity without conducting a full search.
Is my thinking incorrect in some way?
That's a bit offtopic, lol. Well you sound like me from a couple years ago. Atheism, for most, is not the claim of fact. I'm simply saying I'm without a theistic belief system. I went from a Baptist upbringing, to assorted new age/eastern beliefs, to a "higher power" in Alcoholics Anonymous, to Episcopalian, to deist, to agnostic, to currently atheist (pending further evidence

). Each step rendered any sort of God obsolete, and to each of the people in my former life I was already an atheist as I lacked their flavor of theism. I no longer mind the title, and it adequetely describes my stance--the Christian God of my childhood certainly does not exist according to the evidence--I can say the same for most mystical beings that are represented in the world's major religions. To the believers of these religions I am atheist.
But deism, panthesim, etc...what a tempting bastion of ignorance, most recently exploited by the Insane Clown Posse. Look around us--God is everywhere! There comes a point, right about when the belief becomes unfalsifiable, when holding on just isn't worth it. If God is some unseen being that has no effect on reality, how do we go about becoming gnostics? As far as flying around the universe looking for God--if there was a "supreme deity", why should I have to fly anywhere? Shouldn't God be everywhere? Are we to remain happy in our agnostism, a sort of psuedoskepticism, merely shrugging our shoulders in an eternal "iono?" from the backs of our great white horse?
Or, as skeptics, do we consider the evidence, and adjust our reality accordingly?
There are a lot of smarter people on here who were not only instrumental in my atheist "conversion", but have a much better gift with words and tact. A short forum search shows the "atheist v. agnostic" battle ad nauseum, with intelligent folks on both "sides", and even myself from as recent as a year ago arguing the same argument you just gave me.
In the end, the conversations are much more interesting when introducing myself as an atheist
/offtopic