Not all people who use netctl want wifi-menu.
> it isn't mentioned anywhere in the documentation
It sure is. https://wiki.archlinux.org/index.php/Installation_guide -> https://wiki.archlinux.org/index.php/Network_configuration -> https://wiki.archlinux.org/index.php/Netctl And there on the top of the netctl page it lists in a table dialog as a dependency of wifi-menu.
> Which sort of ties into my next problem which is that Arch simply isn't opinionated enough.
Maybe, but not all people have the same opinions...