Power users can use CLIs quite easily on macOS. The official documentation is geared towards the non-power users but information about most tasks a power user wants done in a CLI are available, it just requires a power user skill of searching for it.

It's a good filter, keep it simple and easy for the vast majority of people, and have tools for the advanced ones to use.

>Why does macOS tell you to use the GUI so much?

Because it's whole point is that it's a graphical OS.

If you used just cli unix userland, might as well use Linux.

> macOS idiosyncrasies and its aversion to CLI

But people using OSX often also know the commandline quite well - at the least better than most windows users. I saw this again and again in university.