That "Engfish" essay is strange. It's right that textbooks and so on encourage students to write in a way that's impersonal and overly verbose. But it doesn't recognize the advantages of academic English. It doesn't even seem to recognize the role (or existence!) of dialects in general. Instead, it takes bad examples of academic English (the writing textbook) and suggests they should be more like bad examples of informal English (the third-grader).