Why a gun?

Why would anyone...ANYONE ...want to own a gun? A gun is for shooting.  A gun is for killing. That stupid statement that members of the gun lobby (gun lobby???) say about "it's not guns that kill people, it's people who kill people" is rubbish!  How ridiculous! How crazy! Sure, it was a person who killed those children (& adults) in the USA school, but it was a person who was using a GUN!  If that (obviously extremely deranged) person did not have access to a gun, he may have punched a hole in a wall...or even punched his father. How come a 20 year-old male has access to a gun that fires multiple rounds of ammunition? Sure, in the old "Wild West" they had guns, and, according to the old movies, men would have a stand-off, face each other and then shoot. One shot, maybe two. But dozens? Maybe hundreds? What's that all about? Why would someone, (anyone?) even want to have a gun that was able to fire so many, many, bullets?
I just don't get it! Is it too late for the USA to stop this sort of thing? Too late for them to make the keeping of guns illegal? Sadly, I think so.
And..why do angry, mentally ill people who hold grudges, go to schools and kill children? I don't get that, either. Does anyone?
One of the saddest things I have just read is that, after the nearby hospital prepared for "incoming wounded" (as in M*A*S*H, for God's sake!) there was hardly any need, as the gunman had made sure that almost every little person he shot was shot dead.  Only three little ones needed treatment for wounds. All others, who weren't lucky enough to escape the onslaught by hiding in a classroom closet, were shot dead. Who, on earth can imagine that horror?
WHY DO PEOPLE HAVE GUNS? WHY? WHY?
I can think of no reason for owning, let aone using a gun.  They are evil