I'm in love. Too bad she's an atheist. But I expect in time she'll come around. If I had seen nothing but Islamic barbarism and brutality in my lifetime I might be an atheist, too.
She never said that, she said was not Christian, Jew or Muslim. There are countless other possibilities. An atheist is one who believes there is no God, there are all sorts of beliefs in God and many of those do not fall into the 3 organized religions listed above.
I think what she told him was that what she was was none of his business.