Kubernetes only runs on linux, so it follows to reason if you care about k8s you should care about linux. My experience is also that good experienced sysadmins often use linux for their own machines as well.
Targetting a tool at macOS users, and omitting linux instructions, gives the impression that the tool isn't targeted at sysadmins or hackers (i.e. at us), but rather at beginners, frontend developers, etc.
Saying it's targeted at beginners because it supports MacOS shows a lot of disconnection with what many DevOps people use these days. The year of the linux desktop has yet to arrive, and Mac is king for people in IT (at least in the US)
I have yet to meet a competent sysadmin that cares much about "desktop", and to the extent they do they mostly seem to invent their own graphical tools, with Tcl/Tk and so on.
Most, however, do not, nor should they be expected to. Homebrew is not a safe or viable package manager, especially when better and safer package managers exist in the Linux ecosystem.
