Why are butterfly knives, nunchakus or switchblades sometimes illegal when guns are always legal?
Your question has a few holes in it. Where are guns always legal? You have to register all of your guns and/or have a permit to carry a concealed weapon. If you do not have either the registration or the permit you have an illegal fire arm. I would not consider any of those weapons listed above as less dangerous. A pencil in the hands of someone who knows what they are doing is just as lethal as any of the weapons you listed. Butterfly knives, numchakus and switchblades all sound like weapons of choice for high school trouble makers. Any weapon, knife, gun, etc. found or used on school properties, the owner or holder of said weapons will face crimial charges.