The complaint is fair though. Trying to find a complete or the "correct" guide to something is very difficult even when you already know roughly what you are doing.

I took me ages to work out how to setup postfix properly from about 10 slightly different "guides". The Postfix book wasn't even that helpful. There are also lots of very out-of-date guides that might have been OK for 2015 but not anymore. They don't get deleted because "link juice"

It is sad but true but you get one little bit wrong and you potentially leave a door wide-open.