Atheism is a faith based belief, despite all attempts by any atheist to claim otherwise. Atheism "claims" to prove a negative.
Atheism is not a faith based belief. It simply states that God does not exist. Furthermore, there’s nothing to prove when faith (or Faith) is involved - one does not prove or disprove faith.
It’s wrong to say that atheism is the assertion of a universal negative when atheism is essentially nothing. A satanist, on the other, would better qualify for the assertion. That said, I doubt atheists exist.