There's a difference between correlation and causation.
"Studies have shown" that use of pornography is rooted areas of the brain responsible for obsessive/compulsive behavior. In fact, the same areas of the brain that are stimulated by drugs like cocaine. Use of pornography is often based on conditioning, not merely some primitive biological need to procreate. If human behavior were that rooted in biology, then you would only see us running through the forest humping, eating, and killing.
You seem to have a positivistic view of biology that would be more at home in the 1800's.
I don't disagree with your conclusion, but there are flaws in the logic of how you got there. You are trying to give a purely biological explanation for behavior that is primarily influenced by *conditioning.* That's the key word here.
Anyway, I'm done with this thread. If you want to use your testicles as justification for your urges or you are blissful in your turn of the 19th century knowledge of human biology, who am I to judge.