Weapons are designed to kill people, and yes, you'll find plenty of other stuff to kill people with, but the weapon industry is specifically built on wars and corpses.
And wars and corpses aren't going away any time soon. The second nobody is ever killed by firearms again, then it will be time to give them up. Until then, fun and danger will make love to each other among the sane ones, and violence and killing among the not-so-sane/moral.
The Bush family sold weapons to Osama before they started hating on each other, Russia hinders Europe to do anything about Syria because they sell weapons to Assad. And those are only some of the more obvious examples.
I would actually like a link on the Bush one, because that's the first I've heard that one.
More importantly, those are militaries. They have, quite literally, zero bearing on an armed civilian population. They will be made regardless of if we have nuclear weapons or water guns.
Even though the average civilian will not kill anyone with a gun, I think it is morally wrong to employ guns if it is not strictly necessary. 'because it is fun' is not enough of an argument in that context, at least that's how I see it.
Don't actively try to bring your own morality and force it upon others who don't share the same views, especially when your morality isn't backed up by statistical evidence. Gun rights are not a morality issue, they have no room for personal feelings or views. They are a logical, objective issue. If morality was the main backer, you would have some places with Atomic Annies and others completely devoid of legally owned weapons.
The only basis upon which laws should be created is the basis of statistical evidence and evaluation of risk. These do not need to be such static issues. If automatic weapons, for instance, were fully legalized and machine gun murders went through the room immediately following this legislation, I would immediately kick myself and start a political career to fix the failure. Of course, they wouldn't, because machine guns would remain prohibitively expensive and it wouldn't make sense for criminals to buy them when they can buy twenty pistols and ten shotguns for the same price.
This is not a necessity issue. People have different tastes in what is fun and what isn't. If some people like shooting things, then let them. If there is no logical or statistical evidence that what they're doing will hurt other people, then stopping them is a pointless, costly, and restrictive practice. It doesn't matter what they use their weapons for, so long as they aren't hurting anybody, going after them is just going to cost money we don't have, and likely just lead to a very sour taste in their mouth, and the mouths of everyone involved.
If you don't like the practice, just avoid it. Go after issues that actually matter, such as stopping the
illegal gun trade, not the legal one.