'Just' because:

A rabbi was asked by one of his students “Why did God create atheists?” After a long pause, the rabbi finally responded with a soft but sincere voice. “God created atheists” he said, “to teach us the most important lesson of them all – the lesson of true compassion. You see, when an atheist performs an act of charity, visits someone who is sick, helps someone in need, and cares for the world, he is not doing so because of some religious teaching. He does not believe that God commanded him to perform this act. In fact, he does not believe in God at all, so his actions are based on his sense of morality. Look at the kindness he bestows on others simply because he feels it to be right. When someone reaches out to you for help. You should never say ‘I’ll pray that God will help you.’ Instead, for that moment, you should become an atheist – imagine there is no God who could help, and say ‘I will help you’.”
— Martin Buber, “Tales of the Hasidim”