Often uttered by an unconscious or unarticulated materialist (that is, most people), sometimes to challenge the Gospel (even though they don't know that), other times as a true plea.
How to answer it?
Most Christians will attempt to defend their positon, but wrong. Attack their position.
"Let me ask you a question (Mr/Ms Atheist), why is it important to you that the meaningless random chance universe 'did' this? How come the meaningless random universe doesn't care that [bad thing] happen? What do you want the universe that you believe in to do? It only does the random things which includes meaningless death...but in as random meaningless univerese, everything is meaningless."
"Evolution is about the death of the weak and the survival of the fittest, you're upset by the real world you belive in doing what evolution must do. If your world view falls apart for you, its not much of a world view, whereas I know why it happened, I know God's remedy and I know its full of meaning."
Either might start a conversation; but don't let the atheist think they ever have a position that's viable.
Another approach pops up when a person might think they believe in God (or 'god') and asserts that God/god is not doing his job...in different words, of course.
"Let's think about it. You turn your back on God every waking moment and then when your life strategy is shown to fail you want God-the-fairy-god-mother to bail you out. You've rejected him actively, and you life in the world that rejects him actively and wonder why it turns to dust. You are just like the bloke who only sees his girlfriend when he wants a (insert crudity of choice)."