Is there any other argument in favour of this game other than "it's freedom of speech, so it's good"? That stems from an admirable, but narrow premise: that the freedom of expression should be a virtually unlimited and universal freedom,
regardless of what is being expressed. Why
can't the public say "screw you, you're not bringing that




in here" when they're faced with something that is completely opposed to the common standards and morality? (NB: since censorship is strictly limited and regulated, this means you can't get widespread prohibition of anything that people simply dislike, which deflates that counter-argument.)
In an ideal world, people wouldn't be influenced by violent or sexual media. But we're not
in an ideal world, and ideas
can exert a harmful influence. Not just on the mentally unstable, either. This isn't hyperbole, but demonstrable fact. At its simplest and most benign, it's the reason advertising and product placement work so well.
If you take the line that "Everything should be uncensored unless it's libelous or slanderous', then you get left with a pretty sorry state of affairs. Suppose someone films himself abusing a child. He's rightly caught and imprisoned; should the police then market the film? It's only a recording of something that's already happened, after all, so no-one 'really' gets hurt by the recording itself. The victim's face could even be obscured or altered if there's a risk of defamation. To say that "it might encourage other people to do the same" is irrelevant, because
responsible adults shouldn't be influenced by media. The perpetrator of the crime doesn't profit, so that eliminates the argument that "it allows someone to profit from committing an abhorrent crime." When you examine every argument and counter-argument in depth, you're left with one line:
this kind of publication should be banned because it deserves to be banned, and should not be permitted because it is inherently bad and/or harmful. Either that, or "it's free speech so it's ok".
(I'm aware that I've deliberately chosen an extreme example for this little analogy; just my way of boiling the topic down to its fundamentals.)