The command line (terminal) is the most efficient way to do things in Linux, imo. While it is possible to do the same with a file manager, I think it can be harder to do precise instructions that way.

my guess: it's usually the most standardised part of a setup, also there's no need to try to get your favourite text editor to write to "protected" files

Because you can do the most things on the command line!

because TRUE Linux users only use the command line - crawl back to Windows, scrub!!! 🤡🤡

Some people have issues with text editors and none with terminals ;-)