My logic (take it or leave it) is that since zsh is not the default distro nearly anywhere (Kali?), a randomly selected person who might read that advice (and subsequent advice ITT), would likely find "Use ZSH" includes a shell change and therefore more learning curve than "add a few lines to .bashrc".
This is getting off topic, pedantic, and (maybe?) argumentative so I'm calling it quits. Cheers.
