why people like vigilantism?

Vigilantism is illegal and immoral. We have a legal system and a due process. When police act as judge and jury the end results is police brutality. It is OK to issue a citizen's arrest and detain an alledged criminal until the police arrive. When a heinous crime has been committed, it may take some doing on the part of a number of people to detain a criminal. However excessive force should never be applied under any circumstances. Excessive is a subjective term. I remember when the Night Stalker (a serial rapist) was taken down by local residents, he received quite a beating. Their excuse was that he was attempting to get away and they did what they had to do to detain him. They did turn him over to the police. Was that vigilantism or a citizen's arrest under extreme circumstances? On the other hand, a few years ago, Rodney King, a Los Angeles resident was stopped for a routine traffic violation. Police discovered he was drunk. Rather than arresting him and taking him to jail, Mr. King was severely beaten and the news spread around the world. We don't like to think of our law enforcement officers as being vigilantes, but is there another label that fits better? I suppose these are the kinds of issues and questions that keep attorneys busy.