The problem is not the 99% of situations that you can memorize, but the 1% of times when you realize you have made a mistake and strayed from your beaten path into the dark scary unknown Git woods where monsters with detached HEADs may be lurking behind every tree, and you have to ask a coworker or StackOverflow to rescue you...
Reading TFM and understanding TFM are not the same thing. The more intuitive the design of the system, the closer they are. The point people are trying to make here is that git specifically has an uncomfortably large gap between the two.
While people could put in more effort to learn git more thoroughly, there is validity to the sentiment that git could be easier to learn.
I have read the manual many times. But when I only run into an issue once every 6 months to a year or so, its not exactly fresh on the mind. I still like to look it up again, to make sure I'm not working wrong from memory, and about to lose my work.
So you agree that you should Read The Fine Manual when you hit unfamiliar territory? My post wasn't aimed at saying git isn't complicated, but to encourage reading the thorough documentation of the tool giving you trouble rather than immediately shutting off the brain in the face of unfamiliarity.
TFM is often extremely vague in my experience. I always start my journey into the git haunted forest with RTFM, but I almost always end up on Stack Overflow looking for confirmation that commands actually do what I think they do.
Many have and still don't feel comfortable with their understanding. And there's too many of them for inadequacy or incompetence to be a useful explanation.