"in some cases blaming and shaming is justified" - not really. of course, the entire justice system is based on blaming and condemning and punishing guilty perpetrators of crimes, but if you're talking about people who are claiming to be victims, i don't believe they deserve blame or shame. blaming and shaming people leads to others becoming emotional abusers and bullies.
also, saying that "fake" victims are deserving of bad treatment is going to perpetuate the idea that all victims must be questioned and interrogated and assumed to be lying until proven otherwise.