What choice did they have? That or more nuts berries and easy to catch gophers. Which aren’t that easy to catch. At least with a Mammoth you could eat for several months. A little smoke a little jerky and a meat cash in the nearby pond and you are all set. add to that lots of leather for food and clothing.
Ok it is 10000 BC and I come up to you and say “Lets take these sharpened sticks and go get us a Monmouth”. What you you say to me?