I'm obviously pretty late to the party, but whether atheism is a belief depends on which etymology the word is constructed from.
a+theist = not a theist, and this doesn't require any particular belief
ath(eos) + ist = one who hold the doctrine of not-God as true
a+theist = not a theist, and this doesn't require any particular belief
ath(eos) + ist = one who hold the doctrine of not-God as true