I get what you are saying. Keep in mind I'm just saying this would be how we look for causation, not whether it makes sense to actually do something about it.
> That seems the opposite of high. High would be 1 in 2 or 1 in 5.
I guess I'm thinking of how we'd view a side effect in medicine. If 1 out of 1,000 people who had the problem the medicine was supposed to cure were likely to die or cause a death when taking the medicine, it would seem like a high number of deaths. You'll routinely see side effects of things that happened 1 in 50,000 cases being listed as possible side effects of medicine.
> If the effect of everyone playing video games is 1 additional crime per 100 000 people I don't see the problem
Whether this matters probably depends on what violent thing they do. If it is an additional Columbine type event for every 100k people, that would be much less acceptable than one additional instance of verbal abuse by someone in a disagreement at a bar.