It would be easily visible or not visible in the rape statistics if the world had a single variable. In any case, even if the world was extremely simple, 'rape porn' could increase rapes, and we could still observe a decrease in rapes if 'general porn' decreased the odds of rape to a larger degree than rape porn increased them relative to the population that consumed each.

Yes exactly my point...so it sounds like you're admitting this "availability of porn leading to action" theory isn't a very good one? And that in fact it leads to less action given it satisfies urges at much lower cost.