In addition to being a valuable cautionary tale about grocery store etiquette, the story illustrates an important truth about violence and mental health: violence is not a product of mental illness; violence is a product of anger. When we cannot modulate anger, it will control our behaviour.
When anger is directed at a person, that person is dehumanized in our view - meaning, we can do unto them things we would never do to a neighbour.
So, what's the lesson in this for politics? Well, politics is full of anger, personal attacks and bad behaviour that is largely committed by people who feel like they're above others, which ties back to anger.
Hate is not a purifying force - it's a dehumanizing one.
It's time to take the hate out of politics. When you fight fire with fire, all that's left in the end is ashes.