One could easily say drinking water leads to being serial killer. Billions of people watch porn and never have an urge to kill anyone.
Generally speaking what happens when people or groups dislike a certain behavior or activity they want to attach it to some of the "ills of society".
For some people it's violence on TV and in the movies, drugs, alcohol, the high divorce rate, children born out of wedlock and so on. They try to find a "common denominator" for criminals based upon the thing (the person or group) wants to label as being "the cause". We could easily say people with two legs kill more people than those born with one leg!
The reality is every killer has his or her own "triggers" . Some were abused as children, bullied, not accepted by their peers, molested, or born with mental illness such as having (multiple personalities).
As a society we want the convenience of being able to blame one source or point to a specific cause because it would make it easier for us to profile or categorize them. It's too scary to accept the fact that maybe we are all "ticking time bombs". Someone may have gotten laid off from their job, lost their home, gone through a divorce, and decides to go on a killing spree. Another person could come home from a war and becomes paranoid schizophrenia and believes they are following orders from some invisible being instructing them to kill.
David Richard Berkowitz also known as the Son of Sam and the .44 Caliber Killer, is an American serial killer convicted of a series of shooting attacks that began in the summer of 1976. After his arrest by New York police in August 1977, Berkowitz was indicted for eight shooting incidents. Berkowitz confessed to all of them and claimed that he was (commanded to kill by a demon that possessed his neighbor's dog.)
In the mid-1990s, he amended his confession to claim that he had been a member of a murderous Satanic cult that orchestrated the incidents as ritual murder. Speaking of (cults) there are lot of killers that belong to them as well.