And I've learned over the years to never use an example to illustrate a point that I am trying to make. Because people will zero in on the example and miss the point. I'm an engineer, we use examples to discuss concepts. It drives me nuts not to be able to do that when discussing concepts in writing.
And then there are the comments that come out of left field leaving me scratching my head and asking "Did I say that? Where in that post did I say that? How did they come up with that from what I said?" And boy, have I read some crazy responses to things that I have said. I'd give some examples, but I've learned not to do that.
All of this leads to the question: "Can a person, who lacks the ability to comprehend what they read, write a story or article that is comprehensible to others?" I don't have a definitive answer to this question, but my gut tells me "no."