Death, itself, isn't a bad thing. To a child it is a one way ticket to heaven. It is hard on the parents, and family and friends. But to the child, it isn't so bad.
What you probably will ask then is "Why does he allow children to suffer from cancer," or why allowing suffering in general.
The question assumes that love protects from all harm. Well, it doesn't. If God were to protect us from all harm, even harm we wish to inflict on ourselves, because he is "super loving", our lives would not be our own, but rather we would be robots, always doing what he wants us to do.
With freedom comes good and bad things. And love has its limits.
I have lost loved ones to cancer and almost lost my faith. I wondered "Why did God create a world knowing it would come to this?" I finally gave up on getting an answer to my question and let my faith stand alone, without needing an answer.
But I got my answer when I heard about Open Theism. When I understood God created humans without knowing the choices they would make, and yet had a backup plan had they made the wrong choices, It answered everything for me.
