Words are slippery... Atheism could only require faith if it was being used to mean "I believe it's utterly impossible for anything outside the observable to exist" While back here in reality atheism is used for convenience to express the knowledge that one, or a group of religions are clearly impossible.
If you ever wish to progress past simply hurling words at one another you must first define terms.
The US is so strongly monotheistic that here, when someone says "I am an atheist" it's very clear that what they mean is "I am an atheist in regards to the god described in that book you keep trying to enshrine in law."
The religious then tend to point out that it's just as impossible to disprove the existence of "any god" as it is to prove the existence of "any god." With their own words admitting that it's impossible to do either, conveniently ignoring the fact that it's a higher bar to prove "this specific god" over "any god."
What the initial statement indicated was not the denial of the possible existence of any sort of entity outside the universe, It was just the easiest way to say "The internally inconsistent and self contradictory religion you keep spouting is so self-evidently impossible that anyone advocating the idea... is not capable of understanding a rational and complete explanation. Since they will (find someone who can) create a straw man out of my words regardless, they just get .. 'I'm an atheist' "
While it's clearly impossible to make make valid claims about the unobservable by definition.
It is trivial to prove such claims invalid once you get the squirmy little buggers to actually define what they believe.