There are downsides to everything. It's just a bad argument no matter how you look at it, even if his numbers could be accepted at face value (which you've already shown they can't really). We accept 100 deaths a day to drive cars. Almost every action has a risk. More people are stabbed to death than shot with a rifle of any kind (including "assault" rifles). Are we willing to accept that kind of risk with knives? Even if you accept those things as necessary and guns as optional, there are things like alcohol and tobacco which kill far more people. Are we going to double down on prohibition?