What kind of people feel good about treating a woman who had her head uncovered slightly as a serial killer?

Apparently Iran has some dress code and if you violate it, it is punishable by death. They dragged her into the police station and beat her to death. I wonder what kind of person really feels good doing that, taking a vulnerable person into a police station and just beating her. What cowards, she didn't even have a chance to fight back.