How Can a Loving God Allow Such Evil?
In popular culture it is often asked, “if there is a God, why is there so much evil in the world?” Thus, many see the existence of evil as somehow incompatible with the existence of an omnibenevolent being (God). C. S. Lewis properly identified the problem of evil as the problem of pain.
This raises the question: what experiences pain (evil)? The experience of felt pain in the current philosophical climate is considered a bygone from an earlier non scientific age.  The reason for this is that most contemporary philosophers consider consciousness as illusory, and that humans are merely a material composition with no metaphysical aspect (soul) and no libertarian free will. Thus, there can be no evil if no one is conscious and experiences pain. Moreover, there can be no solution to the problem posed by evil, if there is no soul which transcends death and pain.
Now to the problem of evil as being evidence against God’s existence. Firstly, the problem of evil is a philosophical argument that is theoretical in nature, not a scientific problem. Thus, all a Theist need do is provide a defense for Gods justification for permitting evil.
One of the strongest defenses against the argument from evil is the Free Will Defense. Alvin Platinga argued that it is freedom (to perform good more than evil) which might be the justification for God permitting evil.  It may also be the case that freely choosing to do good brings about a feeling of pleasure (a positive hedonic state). If this happiness is good (pleasure is opposite of pain) then the argument against God’s existence can be answered sufficiently.
If pleasure is good and good is the opposite of evil, then one should seek for pleasure to be continual. Moreover, a potentially infinite pleasurable life would be an acceptable alternative to a frustrating and finite existence. In a potentially infinite pleasurable existence, good events would continue without end. This is exactly what the Christian faith affirms; penitent individuals will be saved and live in a potentially infinite state of goodness. It may be the case that God’s justification of moral evil is he possibility for a person to experience perfect happiness; this perfect happiness is contingent upon a choice—a correct choice to be exact. If one experiences happiness and finds it is desirable, then it follows that one would continually seek this happiness.
If God’s justification for permitting moral evils is for persons to experience complete happiness, then what is the relationship of God’s justification between experiencing moral evils from wrong choices? This is a relationship in which the ends do not justify the means; that is to say, the possibility for experiencing perfect happiness is not the purpose for moral evils (choices made by free creatures). These immoral choices are conceptually known by God in his foreknowledge, yet it is not God’s intention for evil to occur. Thus, these occurrences of moral evil are a side effect of endowing individuals with libertarian freedom to choose morally, leading to happiness, or to choose immorally, leading to pain.
The detractor of God might still argue that he should interfere in the cases of wrong choices made by free creatures which would lead to pain. Prima facie, this seems like a strong objection, however, such a notion would render choice meaningless. One could choose morally or immorally all the time, yet God would intervene in the times which might cause pain. Thus, one could never perform actions which flowed from their free choice. Additionally, choices are first made in the mind before being carried out by the body and if God were to intervene to stave off the pain and suffering it would be at the cost of liberation freedom, because God would remove the choice itself. Another problem with this type of argument is that it argues from ignorance; could it be that God somehow already does exactly what the detractor argues he should be doing? It is possible that God already does this; essentially the detractor is arguing from ignorance.
Goetz astutely observes
Unless God eliminates every kind of moral evil by getting rid of such evil altogether (or somehow allows only one kind), there will always be some kinds which God could and should eliminate because they are worse than others. 
This is to say, despite how many moral evils God eliminates, if there remains one iota or moral evil, the objector will bring this forward as evidence that God does not exist, which is again arguing from ignorance (argumentum ad ignorantiam).
 C. S. Lewis, The Problem of Pain, 1962.
 Stewart Goetz, The Argument from Evil, in the Blackwell Companion to Natural Theology, 2012, p. 450
 Alvin Platinga, God Freedom and Evil, p. 30.
 Rev. 21:4 (NASB) and He will wipe away every tear from their eyes; and there will no longer be any death; there will no longer be any mourning, or crying, or pain; the first things have passed away.”
 Goetz, 465.
 Ibid, 481.