I don't have the patience to debate with anyone possessing that condescending, nanny-state POV; it's galling that knife enthusiasts have to justify the usefulness of cutting tools, especially to self-righteous pricks whose philosophy could be summed up as 'we know what's best for you, and we don't suggest, we legislate'.
Just because something's dangerous doesn't mean it's a weapon. A hammer can be constructive or destructive, and something as simple as a lighter could kill dozens of people, if a person were so inclined. Pencils and pens. Weed-killers and rat-poison. A car. A beer bottle. Accepting some measure of danger and uncertainty is necessary if we want to live in a relatively free society. Reactionary legislation is not the way people living in a democracy respond to every sensationalistic news story. If the reactionaries have their way, we'll all be living in a bubble-wrapped world of sporks and tofu.
Pointing out the obvious to the oblivious isn't the most satisfying past-time, so I appreciate that groups like 'Knife Rights' are committed to banging their heads against this particular wall of ignorance. The fact that automatics and balisongs are now safe to own, in states where they were they were very recently illegal, is a victory that serves as proof that perseverance and reason can still yield results.