Why is violence suddenly seen as such a bad thing?

For thousands of years, humanity has dealt with many of it's problems with a very simple and effective problem solver; violence. If you have a problem, the easiest way to get rid of it is to kill it, as that is the only way to truly remove a threat. Many people see physical adeptness as a trait of the stupid and unsuccessful; but physical strength is just as important as intelligence. Strong humans are larger, live longer, can defend themselves better, and move faster. People who say violence is never the answer; What is the difference between someone being killed by another human or being killed by "natural causes"? Think about it, in the wild animals that are weak or peacefully-tempered are almost immediately killed by either starvation or another animal. Why should it be any different for humans? People say that violence is a sign of stupidity and non civilization, but as said before, predators are often more intelligent than their prey. So how can one say that violence is wrong? I am not saying that violence is always the answer to a problem; I am simply stating that violence is not imperatively 'wrong' and is always an option, while not always the best.