Not that these studies arr bad, per se. Every bit of knowledge adds something,
But the results here are very crude and unsophisticated, as far as I can tell.

What about age levels, for starters?
What about about comparing sports with game playing for tension release?
And so on.

Years ago, some parents started an outcry against the violence in cartoons and children's books (the wicked witch was pretty wicked, you know). That was pretty ridiculous,.

This, however is too complacent in its generalizations.
Parents can't afford to be. They have to consider the nitty grityy questions of balancing time spent on certain activities and the effect on general temperament, long before it reaches the level of violent behavior.

This should be considered, but it should not be considered as the definitieve answer.

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