People who carry firearms are far likelier to get shot – and killed – than unarmed people; Banning guns wouldn't bring down gun violence significantly because people who are committing gun crimes are getting their guns illegally in the first place. It would be impossible to get rid of guns. Of course it would be a bad thing because people love their guns for hunting, killing, etc. If your "great purpose" of guns is death, than yes, they do serve a purpose. It's my personal belief that violence and hate only results in more violence and hate. If America stopped killing people, no one would hate us.
I agree with your view about violence and hate up to a point, but think your conclusion is simplistic, not to mention hopelessly optimistic.
Violence and hate will always beget more of the same, but it is generally the case that if there are sufficient men of goodwill on either side, a route out of even the darkest and most hopeless confrontations can be found.
However, there will always, ALWAYS, be a number of people who for reasons of their own (religious, political, personal experience, whatever) are unwilling to put down the sword or compromise in any way for what is generally considered to be the greater good.
There are still plenty of people who view the world through a prism of events that was constructed decades or even centuries ago, or through religious dogma that is similarly ancient in origin, or through the bitterness of personal loss or pain.
If history shows us anything, it is that as soon as the strong lower their guard, those who have traditionally been subordinate to them will frequently line up to take a swing, and that the punches thrown can be inspired by events that the strong had considered to be no longer sensitive. People have long memories.
Then it becomes a question of how long does one turn the other cheek, the answer to which of course will vary by individual, and by the weight and number of punches being thrown.