In that sense, of altering the public mood, by standing up and effectively saying "That's enough". 

A similar thing happened when Bernard Goetz ventilated those attackers on the N.Y. subway and was not charged with anything worse than unlawfully carrying a concealed weapon. He also used the wrong type of ammunition (I am told that copper jacket is not the best for close combat/self-defense rounds) - the violent crime rate went down significantly in the subway and the city in general. 

So in that regard, even though KR says knowing what he knows now, he wouldn't do it again (sounds reasonable) his actions probably changed the nation for the better in some ways.

Cleaning out the gene pool a little is something not everyone will admit to appreciating, but I do. I will gladly buy him lunch.