Hmm.. I have a hypothesis.
People, in aggregate, respond to things outside of their immediate sphere of familiarity with irrational fear.
There was a time when a pocket knife was a common place as carrying a cigarette lighter is. You could whip out a pocket knife to cut something and nobody would bat an eye.
Fast forward to today, where most people are not in a vocation where having a knife handy is very useful, and so people dont carry them routinely. When somebody whips out a knife, "OMG, DONT CUT ME BRO!" is the first thought they have, and further, they cannot conceive of circumstances where somebody would carry a knife without intent to do such cutting on people.
Eventually, I forsee the carrying of a lighter to have equal "OMG!" factor, as people eventually stop smoking. (possibly adopting new and different vices.) Somebody in that distant future will whip out a lighter to melt the ends of piece of rope, or perhaps an old shoe lace so it doesnt fray out-- and "OMG! DONT BURN MY HOUSE!" will be the irrational fear.
This is currently seen with pocket knives, but also with gun ownership. City people by and large have an irrational fear of farmer joe, because farmer joe owns a gun. (Possibly several.) Farmer Joe does not have wild fantasies about shooting city people, yet you would be surprised the number of people who are afraid of going on a summer jaunt out into the rural counties to see the trees and wildlife, because they are CONVINCED that farmer joe is waiting for them to show up, gun in hand, and that he will start discharging it at them with heated passion or something. They have great difficulty conceiving of reasons why Farmer Joe would own guns, if not to shoot them at people. (Many view guns as existing exclusively for shooting people. when this is simply incorrect.)
Strangely, very few people seem to reflect on this kind of thing though. Certainly not enough to question their own behavior, and impulse reactions to seeing things that to them, are out of the ordinary, but are really completely harmless.