It bothers me that you take positions on psychological questions without citing the generally accepted views in the field at all. With all the criticism of psychology, its conclusions still have more value than gut feelings. And I do not mean only your present answer. For example, see here as well (the last comment):

https://mikyab.net/%D7%9E%D7%99%D7%9C%D7%99%D7%9D-%D7%99%D7%9B%D7%95%D7%9C%D7%95%D7%AA-%D7%9C%D7%94%D7%A8%D7%95%D7%92-%D7%9E%D7%91%D7%98-%D7%A2%D7%9C-%D7%90%D7%A0%D7%98%D7%99%D7%A9%D7%9E%D7%99%D7%95%D7%AA-%D7%A2/#comment-14130

As for our issue, there is a consensus among social psychologists that violence of any kind increases violence (contrary to the catharsis hypothesis), and according to many studies, violent video games affect the viewer and draw him toward violence. Such games do not have a positive effect.
As for sources for a “halakhic prohibition,” one could cite the words of Maimonides in the laws of repentance: “Do not say that repentance applies only to sins involving action, such as sexual immorality, robbery, or theft. Just as a person must repent from these, so too he must search out the evil traits he has and repent of them: anger, hatred, jealousy, rivalry, mockery, pursuit of money and honor, pursuit of food, and the like—from all of these one must repent. These sins are more difficult than those involving action, because when a person is sunk in them, it is hard for him to separate from them. And so it says: ‘Let the wicked forsake his way, and the man of iniquity his thoughts.’”

Indeed, I do not have much trust in that field, and I am also not familiar with its accepted and unaccepted views (I mentioned something I happened to hear, although it was from a serious fellow. I know him very well). But even if all the views were as you say, and even if I did trust the field, I would still say the same thing. There is common sense, and violence that is not deranged—even if it causes some sort of change—is not forbidden. All kinds of things cause all kinds of results. So what?

There is some immediate benefit in discharging an impulse in a harmless way. If a person feels great rage and wants to beat someone to a pulp, clearly it is better for him to vent his anger on broken dishes and calm down.

In the long term, this has the price of “the more you feed it, the hungrier it gets.” A person who comes to a pleasurable catharsis through a violent act will feel the need to return to the experience that gave him that sense of release, and here the door to addiction opens.

It is therefore better that a person afflicted by the impulse to violence find catharsis in things that are positive in their essence, things whose repeated practice brings blessing.

Best regards, S. Z. Levinger

To our Rabbi and to S. Z. L. —

I did not ask you to prohibit such games. Of course I agree that even if there is a connection between them and violence, that does not mean they are forbidden (just as there is a connection between alcohol and violence, and alcohol is not absolutely forbidden).

Two things bothered me.
1. When discussing any subject, one should check what the experts in the field think. That does not mean one has to agree with them, but one should mention their opinion and argue with them, not ignore them. When the question is what the consequences of a certain behavior are, one should clarify what psychology says and what the studies show, and not determine it a priori.

2. I already noted that social psychology holds that there is no such thing as catharsis. There is no such thing as “venting” violence. Watching violence does not release hidden energy; it arouses it.
If someone gets angry and punches a punching bag, he is not releasing the anger—quite the opposite: after punching it, he will express even more anger if he is upset again, even in the short term (of course, if one “has to,” it is better to punch a bag than a person).
I do not know what research that “serious fellow” did. I am citing what I learned, and these are the conclusions of many serious studies.

Rabbi, what do you think?

1. I wrote my opinion. Since in Jewish law common sense is enough, there is no need to rely on the opinions of experts, or “experts.” Nor am I arguing with them, so there is no reason to mention them. If I had written decisively that watching violence has no consequences whatsoever, you would be right. But I did not write that.
2. I am not inclined to accept your assertion about what “social psychology holds,” for the reasons above. But here one really would need to know more.