Knives are used for many things, as tools they can
1. Spread butter
2. Cut rope, cut meat, cut drywall and filet fish
3. Spread mayonnaise on bread
4. Cut fabrics for sewing, arts and crafts, etc.
5. Scrape dirt from under my fingernails
6. Make peanut butter and jelly sandwiches
7. Sharpen a pencil
Guns, OTOH have but one use
1. Shoot and kill
MAYBE, that massive disparity in usefulness accounts for why gun control is more popular than knife control, to some degree.