The first question might be is murdering someone morally problematic? The dependent question would be, is enjoying pretending to murder someone morally problematic? If we say yes to the former we have room to talk about the later.
Then which sinful thoughts, words or deeds can we pretend that we are doing for the purpose of pleasure or recreation?
Are there sinful recreations? And if so, are such recreations sinful in themselves or by what they bring out of us, what effect they have on us, or what effect they have on our relationship with God, our neighbor or the community?
A related question would be, are these kinds of things good as long as they are in the heart and not manifested as an external action?
One issue that would need to be reconciled is that when murdering a fictional person in a video game, there is no actual violence; a second would be that there might be no actual anger. The reason that would be important is that in Jesus’ exposition of the Ten Commandments as the continuing expression of the moral law of God, He said “I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment”. And then later, “That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart. And if thy right eye offend thee, pluck it out, and cast it from thee”
If one is merely looking at pictures of virtual women there is no actual woman corresponding to the graphic, only all of them. Similarly, if one is playing a level of a video game and murdering an innocent or hundreds or thousands of them for pleasure and recreational purposes, is that then a moral good? Being that no action of men or angels is morally neutral (we being created for conformity to the likeness of Christ as instruments of worship) though many are by our merely human estimations, morally ambiguous.
Is pornography, by analogy (and we need to use an analogy of some kind because there seems to be few things left that prick a Christian conscience) a moral problem in itself, a moral problem as used, or a moral problem of production and distribution? What of patently obscene materials? These even by the morally and often legally absurd Supreme Court of the United States were found to be legally unprotected materials under the United States Constitution. We’re they wrong?
Ethical scholar Dennis Prager famously argues that in his historically dependent tradition of the pharisees, there is no moral error with producing, buying, owning or using pornography because the actions are entirely inside the person’s heart and he never touches the woman, and thus remains clean because God would never judge the heart. He goes on to argue for the legitimacy of the Christian or Jew patronizing strip clubs and other such institutions because there is no actual physical act correspondent to the internal desire or actions of the mind and heart.
Child pornography is still illegal even if entirely the product of an artist’s creative labors, even if it does not correspond to any actual existing child. Does this make sense? Since it is the regulation of what is ultimately reducible to imagination and the product of the depraved mind but not external actions?
At this point, child pornography and more general pornography are still grounds for church discipline, but the institutional church because peopled with men, usually follows the world around looking for ways to seem more sophisticated and respectable.
But as for now the church can and must maintain vigilance especially in regard to the care, shepherding, repentance, and restoration of erring members that might fall into sins of sexual moral depravity, without being quite so sensitive to what the world will think of us should we reject something they love, because we love something they reject.
The ease and availability of this kind of internally degenerative material is shocking to the conscience and available through every communicative electronic medium, and quite frankly, the producers of these materials want our young men. They want their minds, they want their money and they want them for the long haul. We know of course that temptations and trials don’t always lead to repentance and faith but are often the means to infidelity, moral failure and eventual apostasy. Apostasy generally happens one sin at a time and not all in a lump.
I think we can at least say this, as a Christian pornography and gratuitous violence as recreations are neither value free nor left to the discretion of the individual conscience.
Practice makes perfect for well or ill.
And we become that which we love in our hearts, “for as a man thinks in his heart, that is what he is”.
This has a lot to do with the training and shaping of a Christian conscience; what a Christian will find disgusting and unacceptable can be changed through ongoing exposure to and accommodation toward injustice, fleshly indulgence, unchaste thoughts, immoderate humor, etc. Purity is one with responsibility not because we do not have Christian Liberty, but because we do.
Contrary to much contemporary Christian thought on the matter, Christian Liberty is not the justification for the Christian to practice myriad evils without the nagging weight of conscience, it is being free from the dictates of mere human judgement in regard to arguable matters. Christian Liberty says yes to all that God says yes. Fleshly indulgence says yes to all that shares its passions. The laws of God are the only arbiter in these matters.
As R. C. Sproul writes on this: “The tragedy of the contemporary evangelical church is its failure to know and establish the law of God.”
For example, The Wesminster Large Catechism in its judgment upon what thoughts and actions are obedient to the law of God within the bounds of Christian liberty says this:
Q. 135. What are the duties required in the sixth commandment?
A. The duties required in the sixth commandment are, all careful studies, and lawful endeavors, to preserve the life of ourselves and others by resisting all thoughts and purposes, subduing all passions, and avoiding all occasions, temptations, and practices, which tend to the unjust taking away the life of any; by just defense thereof against violence, patient bearing of the hand of God, quietness of mind, cheerfulness of spirit; a sober use of meat, drink, physic, sleep, labor, and recreations; by charitable thoughts, love, compassion, meekness, gentleness, kindness; peaceable, mild and courteous speeches and behavior; forbearance, readiness to be reconciled, patient bearing and forgiving of injuries, and requiting good for evil; comforting and succoring the distressed, and protecting and defending the innocent.
And on how we break the law of God under Christian Liberty, this:
Q. 136. What are the sins forbidden in the sixth commandment?
A. The sins forbidden in the sixth commandment are, all taking away the life of ourselves, or of others, except in case of public justice, lawful war, or necessary defense; the neglecting or withdrawing the lawful and necessary means of preservation of life; sinful anger, hatred, envy, desire of revenge; all excessive passions, distracting cares; immoderate use of meat, drink, labor, and recreations; provoking words, oppression, quarreling, striking, wounding, and whatsoever else tends to the destruction of the life of any.
The laws of God are the ethical expression of the nature of God as a personal being involved in the faith and life of His Church. Far from their being something irrelevant to contemporary Christian faith and practice, they are contemporary Christian faith and practice.