To kill or not to Kill?

To kill or not to kill? Why do we kill? Mark Twain offers a simple yet non-applicable antidote to those very questions. In my opinion this quote means that man kills out of fun, malice, and revenge. I agree that man kills out of revenge. However, I do not agree that any sane man kills another human out of fun. Hunting, fishing, and trapping can understandably be fun to many sane men. I agree that killing to satisfy for the three life necessities, food, water, and shelter is reasonable.
The reason this quote is non applicable to our modern society is that his opinions are very subjective, meaning that they can be understood and taken in many different contexts. I agree that all creatures kill, I do not think that man only kills out of malice and re...