Why do celebrities interfere with criminal system?

Kim Kardashian West helped save death row inmate Rodney Reed from execution, inspiring others like T.I., Meek Mill, and Rihanna to voice their support. The Face asks, and tries to answer, why do pop stars, and should they at all, do these things. The dilemma celebrities face - "risk speaking up, pissing people off, and maybe appear to be a craven opportunist, or risk staying silent, perhaps betraying their conscience, and appear irresponsible and cowardly". Professor Mark Harvey says they should do it because it works: “We have politicians that do a great job of commanding media attention but based on my research, celebrities are much better at doing it, even on political issues [and] even competing with presidents”.