I agree that bad documentation is a serious problem in many cases. So much so that your suggestion to write the documentation after the fact can become quite impossible.
If there is only one thing that juniors should learn about writing documentation (be it comments or design documents), it is this: document why something is there. If resources are limited, you can safely skip comments that describe how something works, because that information is also available in code.
(It might help to describe what is available, especially if code is spread out over multiple repositories, libraries, teams, etc.)
(Also, I suppose the comment I'm responding to could've been slightly more forgiving to GP, but that's another story.)
If there is only one thing that juniors should learn about writing documentation (be it comments or design documents), it is this: document why something is there. If resources are limited, you can safely skip comments that describe how something works, because that information is also available in code.
(It might help to describe what is available, especially if code is spread out over multiple repositories, libraries, teams, etc.)
(Also, I suppose the comment I'm responding to could've been slightly more forgiving to GP, but that's another story.)