Humans are the most deadly predators that the planet has ever had. Killing stuff is what we're really really good at. Making weapons is something we're really really good at.
Actually, making tools and organizing labor is we're really good at.
Exactly. And tools and organization are the two most useful skills... for efficiently killing things.
I personally have never killed anything larger than a bug in my life; I suspect a lot of other people haven't either. I've never had to, because there have always been other people who are willing to do those unpleasant tasks for me, in exchange for modest amounts of money.
Paying somebody else to do it turns out to be a very efficient strategy for killing.