I went back and forth on this one because there are so many angles. He raped a 13-year-old! But--he had a plea deal for no jail time, but then the judge had an ex parte communication with a prosecutor and decided to throw him in the hoosgaw anyway! But--that doesn't justify fleeing the jurisdiction! But--his wife was murdered when she was pregnant! But--he thinks he can get away with anything just because he's famous! But--his mother died in the Holocaust! But--he raped a child! But--the now grown-up victim doesn't want him to go to jail!
I decided that I think the last thing is the most important: the woman who was the 13-year-old victim has forgiven him and moved on with her life, thinks he understands that what he did was wrong, and doesn't want him to go to jail. The response to this is that crimes are committed not just against the victim but against society/the state, and that it's up to society/the state, not the victim, to decide the appropriate punishment. But the criminal justice system does, at least sometimes, take victims' positions into account--that's the point of the "victims' rights movement," which allows victims of crimes (or their families) to speak at sentencings and parole hearings. It's true that there is also a movement towards prosecuting domestic violence even when the victim does not cooperate. I think that's a generally good development, because it makes the statement that domestic violence is wrong and will be punished regardless of whether the abuser is able to pressure the victim into recanting or changing her story.
Bringing charges when the victim doesn't want them brought is, in some ways, paternalistic--it's basically premised on the idea that the victim is not able to decide what's in her best interests. But I think that is an ickiness worth dealing with, in fairly limited circumstances. It is reasonable to say that domestic violence should be prosecuted without victim cooperation because domestic violence victims are likely to systematically support underprosecution of their abusers, and that underprosecution is bad for society as a whole.
I do not think this same rationale applies to Roman Polanski's rape victim. She is not in some kind of long-term abusive relationship with Polanski such that he is able to pressure her into blaming herself rather than him. She's a well-adjusted grown-up with 3 kids of her own who hasn't seen Polanski in 30+ years. If she doesn't want him to go to jail, I dont think everybody else should second-guess her.