Internet porn reduces rape?

An article in Slate concedes that the increase in the use of internet porn has a direct correlation to a decrease in rape. He also contends that violent movies decrease violent behaviors and crimes. Now theoretically, this is plausible, but his logical leaps are a little grandiose.
Have at it.

Does pornography breed rape? Do violent movies breed violent crime? Quite the opposite, it seems.
First, porn. What happens when more people view more of it? The rise of the Internet offers a gigantic natural experiment. Better yet, because Internet usage caught on at different times in different states, it offers 50 natural experiments.
The bottom line on these experiments is, “More Net access, less rape.” A 10 percent increase in Net access yields about a 7.3 percent decrease in reported rapes. States that adopted the Internet quickly saw the biggest declines. And, according to Clemson professor Todd Kendall, the effects remain even after you control for all of the obvious confounding variables, such as alcohol consumption, police presence, poverty and unemployment rates, population density, and so forth.

This may very well be true, but I would be interested in seeing some other factors that may be involved here, like law/policy, work by anti-rape activists, etc. Furthermore, whether this decreases rape or not, does the use of internet pornography change the culture of rape, or does it justify sexual fetishization to an even greater degree. Don’t get me wrong, the less rapes the better, but is this a solution?
The author (Landsburg) continues admitting that correlation may not be causation.

OK, so we can at least tentatively conclude that Net access reduces rape. But that’s a far cry from proving that porn access reduces rape. Maybe rape is down because the rapists are all indoors reading Slate or vandalizing Wikipedia. But professor Kendall points out that there is no similar effect of Internet access on homicide. It’s hard to see how Wikipedia can deter rape without deterring other violent crimes at the same time. On the other hand, it’s easy to imagine how porn might serve as a substitute for rape.

The article also discusses violent images and violent crime, one theory being if violent criminals are watching a movie, then they are not outside committing a crime.
Thoughts?