Well, aside from the fact that rape is more about power than sex, the link between rape and pornography is well documented. Using pornography also causes changes in the brain that make the user require more explicit and harder core pornography as the weaker stuff stops giving the same high. It's like a drug, but even more powerful.
Also, the fact that something happens after something else doesn't prove the first thing caused it. That's a fallacy in logic. But who studies logic these days and how many people are critical thinkers?
Here's the comment I posted on the blog -- probably pointless. Many people these days will believe whatever they want to believe and facts don't make a bit of difference.
The link between pornography and rape has been well documented. http://www.drjudithreisman.com/archives/2006/09/pornographys_li.html
James Dobson interviewed serial rapist/killer Ted Bundy who described the serious impact pornography had on his crimes. http://www.pureintimacy.org/piArticles/A000000433.cfm
It's counter intuitive to think pornography, especially S&M doesn't contribute to the problem. If violent video games can be linked to increased aggression and violence in those who play them (http://www.slate.com/id/2164065/) why would porno movies, especially those showing forced sex, not have the same impact? Those who don't think there is a link need to provide some evidence to back up their opinion.
I think the decline in rape is more likely due to the fact that the population is aging and that over the last two decades men's testosterone levels are declining. http://www.ourstolenfuture.org/NewScience/reproduction/2006/2006-1210travisonetal.html
If there are fewer younger men, there will be fewer rapes. Dirty OLD men may expose themselves amd be peeping Toms, but many can't do much else.