I'm sure there are better articles if you search more. If you have time for a book, I highly recommend "The design of everyday things". If you don't agree with me that book will change your mind.
You get used to it as in "used to how CLI programs are usually designed". Just as you get used to what the select icon in a GUI does. Without any prior experience in any both seem like alien technology, but coming from GUI to CLI you have the bias of already knowing one when comparing.
People claim macOS is intuitive and everything works the same, but I'm handicapped in it. I just call it inexperience not being bad UX.
Regarding the manual, does GUI programs have a unified way to access guides and documentation? Can I scroll to the bottom with G and find the configuration files and example uses?
The difference is, you can teach a user who's never seen a computer before to work with a GUI in an afternoon, maybe a weekend -- and if the GUI is well-designed, the skills they learn on one program will transfer well to others.
Meanwhile, there are XKCDs about how even experts can't remember how to work tar: https://xkcd.com/1168/
Before 1984, computer UX was, universally, sucky. As Alan Kay put it, the Mac was the first computer worth criticizing.
Ease of use isn't the only metric for "peak UX" though, composability and how the programs interact should also be taken into consideration. Selecting a filter on instagram is very easy, with the caveat that you're limited to those filters alone. The subject is more complex than clicking buttons vs typing commands.
1 second of googling: https://fstoppers.com/opinion/stop-telling-people-read-manua...
I'm sure there are better articles if you search more. If you have time for a book, I highly recommend "The design of everyday things". If you don't agree with me that book will change your mind.