I disagree. If a programmer cannot articulate their thoughts and ideas clearly, and cannot effectively communicate with others through writing, I would question whether they fully understand the concepts themselves, and whether they are actually a good programmer.

Being able to write is a skill in its own right, but it's one which anyone can acquire with practice, and it's one which many programmers would benefit greatly from. Writing code is only one part of the job, and writing documentation, requirements and design is a big part of the rest, and these parts are just as important. It's often the case that the act of writing down these things identifies inconsistencies and omissions which have not been picked up on during design or code review. And, ultimately, your libraries or application need to be used by other people, and if it isn't properly documented it's going to fall short of expectations since people won't be able to use it as intended.