You are right, victim blaming is horrible. That's why I didn't say "they should have said something immediately, now they have lost credibility"
I understand why they might not go immediately and don't blame them for it. I still think the right thing is immediate prosecution. If they don't feel like they will be helped by the authoritiesthat is a problem, which needs to be addressed both on the sides of the authorities (with proper training and procedures) and education (teaching people to prosecute immediately instead of shutting up)