This is exactly correct. But I strongly doubt high school and college English teachers will ever change.
As an English teacher and writer who traffics in factual prose, I’m with Mr. Coleman. In my experience, students need more exposure to nonfiction, less to help with reading skills, but as a model for their own essays and expository writing . . .
What schools really need isn’t more nonfiction but better nonfiction, especially that which provides good models for student writing. Most students could use greater familiarity with what newspaper, magazine and book editors call “narrative nonfiction”: writing that tells a factual story, sometimes even a personal one, but also makes an argument and conveys information in vivid, effective ways.