I do feel that Hollywood was mainly responsible for the outlawing of autos/switchblades in the '50s and balisongs/butterfly knives in the '80s. In fact, I KNOW that Hollywood was responsible for the latter. Lawmakers felt that those 'scary-looking', 'exotic' knives being flipped around by movie thugs were the next big threat to public safety. Meanwhile, cars kill more people every year than all the switchblades and balisongs in the world. They're even being used purposely as weapons, but nobody is clamoring to outlaw automobiles.
In decades past, many street people and thugs used ordinary, non-locking pocketknives like Barlows, Texas toothpicks, stockmen, as weapons in fights. Because that was what they had, and at the time, locking folders were prized but not common. Also, some of them also thought that cheap switchblades were a joke carried by wannabes. I'm not saying that traditional non-locking pocketknives are ideal as weapons, only that there were people who used them as such. People will find a way to weaponize literally anything if they feel the need to.
OTOH, there are some Hollywood portrayals of knives that have been positive, such as SAKs in McGuyver. Even though their functions are often highly exaggerated.
Jim