I can tell an anecdote from my own life to confirm this theory.
My first PR at nixpkgs, I had to close because I didn't understand what the maintainers were complaining talking about, it was like they were speaking a different language.
It was only one month later, after reading other PR reviews, talking on IRC and thinking about all of it, could I make sense of what they wanted from me. Since then I've started doing exactly what the author described: comment on other PRs with things that I was confronted with, and/or saw others be. By now I've gained enough knowledge to come up with own criticisms - indicating that I've learnt quite a lot.
My first PR at nixpkgs, I had to close because I didn't understand what the maintainers were complaining talking about, it was like they were speaking a different language. It was only one month later, after reading other PR reviews, talking on IRC and thinking about all of it, could I make sense of what they wanted from me. Since then I've started doing exactly what the author described: comment on other PRs with things that I was confronted with, and/or saw others be. By now I've gained enough knowledge to come up with own criticisms - indicating that I've learnt quite a lot.