Some people always have wanted to kill other people. It's always a possibility when pros outweigh the cons. A gun just makes it very very easy to do so with extreme violence in a matter of a split second, as opposed to knives or swords that take much longer and less likely to kill. Guns do need to be taken very seriously with extreme caution, but the choice should be made by informed individuals, as opposed to a governing entity making the decision for you.