I for the life of me don't understand this line of arguementation. What point are you trying to prove? This all seems to me like one big non-sequitur.
And what is wrong with an emotional reaction to an event of violence? Is that not the very reason we have a criminal justice system? We long ago chose to delegate to government the emotionally-influenced retribution exacted via lex talionis and vigilantism so that the very rights of the accused are protected, and that he is not swinging from a tree before he recieves due process.
The reason parties who intentionally commit acts of death and destruction need to be swifty brought to justice is rather simple: They're far, far more likely to do it again and when they do, they're more likely to maximize the efficiency of their acts. Also, someone who intends to harm others does so because he wants to. Indeed Blackstone is famously quoted as saying "In order for there to be a crime, there must be vicious will." That's why crimes with lesser degrees of mens rea (think negligence) and strict liability crimes are so controversial.
The difference can be seen not just in our anger to events like this, but also in our laws which provide for harsher punishments when there is a greater degree of mens rea. Note we use the term "greater" because we feel there is far more culpability in the acts for someone who does them purposefully.
Additionally, the anger of the populace must be tempered. Indeed, I think many of us look at accidental mass casualty events with a greater degree of sadness, though the level of anger is generally commensurate with the level of mens rea.
+1000 I just can't believe his train of thought. Its like we're talking about apples and he's talking about oranges.
He has to be doing on purpose.