Let's say my Australian friend had attacked his female sexual assailant. Would he have been allowed to leave? Not a chance! The police would have been called and he would have been hauled away to the police station. Probably he would do time in a Japanese prison, or if lucky deported. Why? Because he's a man and men shouldn't be violent to women.
Indeed women shouldn't be violent either, but we seem to tolerate more violence from them. If a woman is violent we think she had good reason to be; as the train station authorities apparently did by letting Melinda go.
Yes, the man probably would be hauled off to prison. But I think what you call a "double standard" is more a reflection of how power is divided in society. Men, especially men in Japan, still have the balance of power tilted heavily in their favor. To punish the Canadian woman as if she were a man put in the same position would basically maintain the imbalance of power in men's favor. Why? Because women are far more often the victims of sexual violence than men are. To eliminate your perceived double standard would ensure that the victimhood of women (Japanese or giajin) will continue.
Additionally, this Canadian woman's case had a very surprising outcome, considering she was a woman AND a gaijin and therefore more likely to have been blamed for her assault than the salaryman would have been for his assault. It's good that she was at least able to fight back and protect herself without reprisal from the police. In most cases, the Japanese police are completely unresponsive to complaints of sexual harrassment and rape and often take the view that women are responsible for their victimization.
As far as the "ball grabber" situation goes, the man may have had some options open to him, but violence of course shouldn't be one of them. Like I said, the balance of power in Japanese society is already shifted heavily towards men. Allowing them to use violence against women to resolve an issue would tilt that balance even further.
Thus, you might want to reconsider some of the opinions you have written to make sure you aren't endorsing a view that undermines the feminist principles you profess to believe.
