Earlier quoted context omitted.
Agreed. So many of the people who ask questions on the Emacs stackexchange have never even looked at the manual. Emacs has excellent documentation, and often there will be a whole chapter dedicated to answering that specific question. The title of the chapter will have the same key words as their question. And the manual is readable right inside Emacs! But by asking the question on SE, they can get someone else to go…
Excellent documentation? For Emacs? There is such a thing as overloaded and non-user-centric documentation that is rich in details (if you already knew a few Emacs-type keywords)
While it is detailed, it can hardly be called overloaded. The real reference material is in a completely different book, the Emacs Lisp Reference Manual. There is also a FAQ, and if you’ve never programmed in Lisp before then there is the Emacs Lisp Intro. Then there are something like 60 other manuals for various packages that come with Emacs, like Org Mode or the calculator. These all serve to keep the core manual from becoming overloaded with details.
You can read them all online at https://www.gnu.org/software/emacs/manual/>, should you care to try to prove me wrong.
I estimate that about 30% of questions on the Emacs StackExchange can be answered by quoting from that core manual, another 20% by the FAQ, 20% by the Elisp Intro, the Reference, or the docstrings of individual commands, and another 10% by the manual for Org Mode. The calculator comes up occasionally too. Perhaps 10–20% of the questions on the site are actually interesting questions that require real thought or a look at the source code.