well as far as I'm aware anyone who owns a gun must be sick, or else why have a thing that can kill, I mean what other reason is there to own a gun but to kill.

You're right. Ultimately, the only reason to own a gun is to kill. Why is that sick? I own guns though I don't hunt and seldom even shoot at targets. I live in the country where encounters with potentially dangerous animals are pretty common. Over the years I've shot venomous snakes that have taken up residence in my fish pond, feral animals that were attacking my own pets or livestock, and animals that have been severely injured by hunters, cars, or fights with other animals. Are those sick behaviors?