No need to mock, I think we can discuss this without insulting. My understanding of God's nature comes from what the bible says about him that
God is eternal, immutable, infinite, omniscient, omnipresent, and omnipotent. We are not eternal, immutable, infinite, omniscient, omnipresent, or omnipotent and therefore we cannot expect to be able to fully understand God’s ways. The book of Job deals with this issue. God allowed Satan to do everything he wanted to Job except kill him. What was Job’s reaction? “Though he slay me, yet will I hope in him” (Job 13:15). “The LORD gave and the LORD has taken away; may the name of the LORD be praised” (Job 1:21). Job did not understand why God allowed the things He did, but he knew God was good and therefore continued to trust in Him. Ultimately, that should be our reaction as well. I don't want to get wordy but your question, "God chose evolution via natural selection as his tool of creation?" does not follow the original question of this thread. I answered biblically with references.
The Bible makes it abundantly clear that all of us are tainted by and infected with sin Ecclesiastes 7:20; Romans 3:23; 1 John 1:8, (my original point). Now, because we are all cursed by sin none of us are good and what happen to the 10 yrs old kid is terrible but not surprising given human nature. Romans 3:10-18 could not be clearer about the non-existence of “good” people: “There is no one righteous, not even one; there is no one who understands, no one who seeks God. All have turned away, they have together become worthless; there is no one who does good, not even one. Their throats are open graves; their tongues practice deceit. The poison of vipers is on their lips. Their mouths are full of cursing and bitterness. Their feet are swift to shed blood; ruin and misery mark their ways, and the way of peace they do not know. There is no fear of God before their eyes.
According to the bible this is why these types of abuses are common in this sin cursed environment.
HM.
The question regarding evolution via natural selection is directly relevant to the OP's question because it is a variation on the problem of evil, or, the problem of why God seems to allow such suffering and misery-inducing events to occur uninhibited.
The answer is not in the Bible, or else the Christian apologists could point to it and be done. Instead, there is a centuries old debate. The most sophisticated work on the problem came out of the toiling of the Catholics during the Medieval period and was generated from philosophical reflection, not searching for quotes in the Bible.
Unfortunately, the answer you've provided here is not an answer at all: it reduces to the phrase, 'God works in mysterious ways.' It is a recommendation to entirely ignore a problem and pretend it isn't there, while still maintaining one's belief. It is also extremely questionable because the rest of God's apparent plan is entirely intelligible. Why would his handling of suffering suddenly become incomprehensible to us? The need for 'mystery' only appears when an apparent logical contradiction is at hand.
Would you forgive, say, a scientist for such a thing? Imagine that a scientist's theory on the origins of the universe is fully fleshed out, but when an inconsistency arises, he says, "You must believe me all the same; the universe works in mysterious ways," with that being his only answer in response to critics pointing the inconsistency out. This is a copout and a non-explanation whose only purpose is to paper over theoretical difficulties, both for a scientific theory and a religious one (like Christianity). It is a totally unacceptable move to make in any sort of intellectual inquiry.
Regarding sin: there is a variety of suffering that is generated by mindless biological processes, such as mutations that wreak havoc on newborns. This suffering is a result of the tools of creation God chose, not our sin (as it is not the result of humans inflicting suffering upon one another). This type of suffering cannot be accounted for by sin-based explanations such as the one you offer in your second paragraph, as the processes generating it are antecedent to such sin (that is, these processes existed long before we did, and thus before our sin did).