Certainly, rape is one of the most offensive crimes imaginable.
> So?
So the danger is on the Internet you can easily tailor your social circle to agree with you where such a thing would be impossible IRL.
> Is it? How so? What about romance novels?
Romance novels as far as I am aware do not involve crimes.
> Not so fast. Are you assuming that anyone who would watch/read such a thing is trying to work up their nerve to commit/participate in a rape? Or that once they've seen a depiction that they'll be somehow compelled to go and rape someone?
Neither, simply that their fantasy is one of rape, not pretending to rape. If it's just a fantasy then it's creepy but ok, the danger is when an echo chamber is formed and no dissenting voice exists.
> Is it your opinion that suppressing such material would prevent the behavior? Can you support that opinion with evidence? How about the fact that rape has existed before pornography?
No of course I don't believe that suppressing such material would prevent the behaviour. The fact is that many rapists are mentally ill individuals. My hope is that careful management can reduce the exposure these individuals have to reinforcement.
> Is there some proof that viewing or reading such material will cause previously ordinary people to become psychopath/rapists? Or is it merely popular to want to externalize blame for one's actions?
The danger is not to 'previously ordinary people'. The danger is that people with predispositions can be convinced that they are right in their beliefs or feelings. For example, that feminism is against the 'natural order'. That is quite a common one.
> But you want to start stamping it out on the internet first?
Not at all, if there existed such a place where people with rape fantasies could go to discuss them together I would support its closure and perhaps even the monitoring of its participants. It's a fine line to walk but I take issue with the idea that it's either all or nothing. It isn't, responsible measures can be taken without silencing dissent or isolating the vulnerable.