takes one to know one (yikes). I do find it tough when readers attempt to deign a writer's mental state from some groups of characters strung together. Why, some might call that mindreading. '-)
this is how written communication works
The Author generates strings of characters (that ultimately form 'words' and 'sentences' and 'paragraphs' in aggregate).
These character strings are chosen by an author to suggest a 'frame of mind' in order to best get her point across. So when an author of fiction causes a character to say things that are interpreted as angry, it doesn't mean the author herself is, in fact, angry.
Therefore, unless we know something not in evidence besides the author's strings of characters, drawing conclusions as to the writer's mental state is ... odd. Even for pieces of non-fiction.