Sheriff Joe Arpaio
The worst part is not what this guy is doing, but the cheering comments by the ordinary people. Unfortunately, it's known and well studied part of human nature. People can loose any thoughts of morality, humanism and even simple logic the moment, a person in the position of authority tells them, it's Ok to abuse or torture people.
It's hard because so many signals from society -- from media to entertainment -- contribute to this kind of dehumanization.
It's worth pointing out bad examples so people remember not to lose our humanity.