Thanks for your thoughtful and helpful post re: principle of charity and how it applies to autists.
I have met many autists in social circles, who you would never think they were. A woman, extreme beauty, rich, confided in me that when she asks her mother-in-law, "Do you get the newspaper seven days a week", the relative answers, "We don't get it on Saturdays." My acquaintance said, that this meant nothting to her: does the M-i-L mean she gets it on every day but Saturday? To my acquaintance it was an impossible conondrum to solve. Had she known and applied the Principle of Charity, she most likely would have interpreted that the M-i-L meant she gets the paper the other six days of the week.
The language is not as weak as some people think; the language is as weak as the user who uses it. It takes special skills to be unambiguous, and if the speaker does mind if she is misunderstood, then I think the onus is on her to be crystal clear in her communication.
Clear, unambiguous speech is just as inaccessible for most of the population, as for me to access the Principle of Charity properly.
A wise man or woman once penned, "Everybody lies, but it does not matter, since nobody listens." It is true, that reading and comprehension skills are lacking in our world. I wrote just yesterday a post , that I was harshly criticized for, only because the reader neglected to read two words in my argument. I was crystal clear, but s/he glided over words.
My autism dictates that I listen and read every word... can be very uncomfortable when in the company of very boring people.
Anyway, I am rambling. The upshot is, that the Principle of Charity is useful for normal people, who can substitute the gaps in the explanation or the gaps in the steps of logic, or the misspeaches with the right expressions fluently and without error. I believe this is a skill that more befits women. I can listen to a story with my aunt (she passed, this is an old example) and the speaker would talk about a woman, her mother-in-law, and a female cousin of the woman, and in the story she would use the female personal pronoun for all three. I would be lost by the second sentence, while my aunt would follow the story through, without any difficulties.
The sad ending of the story is that I perfectly well see the intention and the logical helpfulness of the Principle of Charity, but alas, I am unable to use it due to my disability. This is not a statement coming of defiance, it is a statement of the sad truth.