This is something of an old chestnut sometimes stated this way: If a good and powerful God exists then he would not allow pointless evil; since there is much pointless evil in the world then either there is no god, or he is not good or he is not powerful enough to stop it.
Hidden in this statement, of course, is the assumption that if something appears to be a pointless evil to me then it must be a pointless evil. As if I were the final arbiter over good and evil!
There are many stories in the Bible which tell of what seems to be terrible tragedy turning out to be a greater blessing. The story of Joseph is an example. Sold into slavery by his brothers out of jealousy, imprisoned in Egypt out of venom and spite, but eventually he rose to prominence as Prime Minister of Egypt and there saved many thousands from famine, ironically including his own brothers.
Of course, for every story where the cloud has a silver lining there are hundreds where the cloud is dense and just gets denser. Because we cannot know the mind of God we cannot say that the suffering is without point even if it seems so. But even if such suffering does not disprove the existence of God it does not help the sufferer who may well feel very angry about his situation.
It has to be admitted that such suffering provides a problem for the believer, but it is just as difficult for the unbeliever.
CS Lewis put it this way:
My argument against God was that the Universe seemed so cruel and unjust. But how had I got this idea of 'just' and 'unjust'? ... What was I comparing the Universe with when I called it unjust? ... Of course, I could have given up my idea of justice by saying it was just a private idea of my own. But if I did that then my argument against God collapsed too - for the argument depended on saying that the world was really unjust, not simply that it did not happen to please my private fancies ... Consequently, atheism turns out to be too simple.
To be true to his tenets the atheist must say that evolution depends on death destruction and violence of the strong against the weak. I watched one of those natural history programs that the BBC does so well. In it a Water Buffalo was bitten in the heel by a Komodo Dragon. The venom took days to work but the Buffalo gradually became weaker until it was too feeble to repel the attack of five or six dragons who began to eat it while it was still alive. The video was so repulsive that even the cameraman broke down. But why? This was only 'nature red in tooth and claw', what evolution demands; why should it upset us?
Similarly, plate tectonics insists that there will be earthquakes where plates abut. If humans build in such places the humans are going to be killed. Why should that upset us? As long as it isn't me or mine, why should I care? Haiti might say something about the stupidity of the town planners, but why should we be upset about the natural world, which is like it is. In a truly secular world there is no place for the concept of horrifying wickedness, and if we find some thing are horrifyingly wicked or pointlessly evil then this is an argument for the existence of God.