Your right. There is strong evidence that porn is harmful. The illegal porn collates with higher rates of violent crime.
I think you misinterpreted what I wrote. I said there was a strong negative correlation between the availability of porn, and rape and murder.
These crimes have plunged since Ted Bundy's day. You need to explain how porn causes violent crime when its increasing availability is associated with a decrease in rape and murder.
http://www.disastercenter.com/crime/uscrime.htm