I don't see why it isn't just as likely for someone, like the person who corrected the use of "he," to decide from context simply that the poster was mistaken about the person's gender, and to treat it like they'd treat any factual mistake. Language is about conveying messages to people, and part of the message that was received was that ratsimihah believed the author to be a man. Grammatically acceptable or not, using "he" as a gender-neutral pronoun here introduced confusion.
