Why is it you can ask the "How many people get killed" question with regard to rubber band guns, but completely ignore the question when discussing "assault" weapons?

Drunk drivers kill 10's of thousands more people each year than criminals with assault weapons. Should we ban alcohol, too? How about we arbitrarily set aside a group of scary looking knives, call them "assault knives" and ban them, too. Nobody needs a Rambo knife, so let's outlaw them! I'm sure a hundred or so people die each year from stabbings using these knives (to use your criterion).