Are all Western atheists in a perpetual fight against imaginary creatures?

I was born and raised in Japan, where the lose of WW2 by our god, swept dogmatic religious notions under the mat. Most people do not think about it, no one argues about it, religious people just are. And they don't try to convince people of their faith, while atheists do not try to convince people that lack of faith is the best. Why do American Atheists care to argue about what they don't believe in? Its essentially like arguing about nothing, while knowing that nothing is true.