People are assholes. Every one of us are, some a lot more than others.
We look for someone to blame. Media and the other side of government that we don't agree with! They look for an excuse. To hell with the man! I don't like people who don't think like me!
The blame and excuses are all bullshit. It boils down to people are shitty by nature and are prone to doing stuff like this. When they do, they should be punished. Contain your anger and use that energy for something positive.