This is for prosecution. The removal of such speech is a civil suit. Facebook/Twitter might have taken a post more serious when the police came and asked questi

This is for prosecution. The removal of such speech is a civil suit. Facebook/Twitter might have taken a post more serious when the police came and asked questions, but then, they might not. And prosecution might not what a victim was after, as this involved being part of a legal case where your stance is weaker than that of the claimed perpetrator (as it is a penal case then).