I think that this may be a case where no generalizable, population-wide correlation can be made but where there are individual cases where a causal, although not exclusively so, relationship exists. It's an interesting quirk of case study vs. demographic or statistical analysis.
No doubt the mechanism of action would be to push or kindle the fragile mind into devaluing women further, increasing the rate; however, porn probably acts as a sexual safety valve for some men, too, cutting the rate of abuse or assault. At a guess, they're probably either insignificant on a population basis or balance each other out or both.
Either way, and I don't mean to step back into last week's BPD discussion, people who score high in antisocial personality traits (through instruments such as the Pyschopathy Checklist) are very apt to attribute their deviant behaviour to external factors. That alone does not a psychopath make, but at the very least one should look at who, exactly, is making the attributions.
m.
,--------------------------------------------------------------------------.
> Marco Anglesio | Chance favours <
> mpa at the-wire.com | the prepared mind <
> http://www.the-wire.com/~mpa | --Louis Pasteur <
`--------------------------------------------------------------------------'