All that is required to be an "atheist" is for a person to decide to use "atheist" as a descriptor.
The descriptor "atheist" is bullshit...meaningless, because it means so many different things to different people.
As for all this "believing"...on the question of whether or not there are gods involved in the REALITY of existence...all one can do is to make a blind guess.
If you want to call your blind guess a "belief"...fine; it is still nothing more than a blind guess. So...blindly guess there is at least one GOD...or blindly guess there are none, if you must.
Much better not to make useless guesses, though.
Yes. I think the extremist Bible-bashing Americans make everything far too simple. My Mother would, at a push, describe herself as an atheist, but mainly she just said, 'Well, you don't tell children there's no Father Christmas, do you?', which was fortunate because my Father was an extremely left-wing Anglican parson (she was a trifle more conservative). I used sometimes to attend Church until they changed the Book of Common Prayer into Committee-ese, and I reckon that very few of the members were great believers in 'God'. In an Established Church you get that sort of thing, and it spread over into a dis-established one like ours.