I don't think pornography has anything to do with people committing crimes. Maybe if someone is a criminal (or mentally ill) already, porn can influence them in a negative way, but I don't think your average man down the street watching it is suddenly going to become a serial killer or rapist. You can say there are statistics about men in prison, but for those to be accurate, you have to question "normal" people who are porn watchers, etc. That's the problem with a lot of studies on crime. They sample the prison population but not the general population.

I don't think anyone is evil simply for watching porn.