Eh, I'm going to have to disagree. Religion isn't just a set of beliefs on supernatural explanations for the state of the world - it's a series of beliefs
in supernatural explanations for the state of the world. Atheists lack such a belief entirely. The distinction is subtle, sure, but it makes a world of difference.
Not to mention, a key part of religion is an adherence to certain rituals and a belief in an absolute, divinely-mandated set of morals - Atheism lacks both of these key qualities inherently.
Some atheists can be extremely dogmatic about their beliefs, sure, but that's neither here nor there.
Actually, that's just deism. Though I will agree, the distinction can be quite murky. Religious belief isn't necessarily binary (Do you believe or not?); it's more along the lines of a spectrum, with an infinite range of possibilities.