When we ask such questions, we imply that if God is good, nothing bad should happen to us—or at least nothing bad to the innocent. Life just doesn't work that way. I've been reading the Bible for more than 50 years and the promises of God are to be with us in our pain and not to shield us. For example, "Even when I walk through the darkest valley, I will not be afraid, for you are close beside me" (Psalm 23:4, New Living Translation).
I wish God had protected me during childhood. I hate the pain I've had to go through. Now—after dealing with my issues for years—I can look back and thank God for taking me through those terrible times. He didn't let me give up, and I'm healthier today. However, that's not all: I care about others in their pain because I can feel what they feel.
Too often we forget the purpose of our ordeals. We come out stronger and more sensitive to the needs of others. We can wrap our arms around the hurting because we know how it feels to be hurt.
I don't know why God didn't intervene.
I do know that I can intervene when others are in pain.