I don't completely disagree with you. And I have read the manual, and there's value to understanding the tool. I've also watched a variety of videos with information, did some experimentation myself, and have certainly forgotten many aspects of the manual too since I don't need it day in day out.
I also know that it's highly impractical to assume everybody who buys one will memorize every part of the manual. I don't use MIDI in any of my guitar setups so I definitely haven't memorized those parts. I may not even have read them to begin with. Instead of "Read the Fickchuckalucking manual" "reference the fickstastic manual" might be more reasonable for most people, until they come across something not in the manual.
I also know it's a pretty big PITA to be dealing with a PDF on a phone screen hunched over an FM3 on the floor at band practice where a referencial search might help you find the info you seek faster.
Two things can be true