It is true that many guns are designed for use against other humans. Handguns mostly, but also millitary weapons and such.
But there are many guns that are designed for hunting or the sport of target practice. Shotguns and rifles are a good example of these. 200 years ago in much of the United States a gun was necessary tool to hunt for food or to kill predators threatening your livestock. I agree that millitary weapons and handguns should have some controls, but lumping all guns together as "human killing machines" is naive and ignorant.