Looks like that section focuses on how to get some vulnerable services running in the lab to test against, which is why Kali isn't on the list as it's an offens

Looks like that section focuses on how to get some vulnerable services running in the lab to test against, which is why Kali isn't on the list as it's an offensive distro for your workstation. Kali is very convenient and well-maintained, but at the end of the day it's really just Debian with a bunch of common security tools pre-installed. I usually default to using it since it's easy to install and I know it pretty well, but it's perfectly reasonable for someone to run vanilla Debian or Fedora or whatever they prefer and customize the tooling themselves instead.