It’s harder to kill someone with a knife than a gun and it’s even harder to kill lots of people with a knife than a gun. This should be extremely obvious, but since it’s not, learn something new every day!
Well the event I’m still addressing concerns 2 people killed, not lots. In general it’s easier to kill someone with a gun, but it is easy with a knife too. The differing amount of effort is no consolation to a dead person.