English classes in the U.S. spend a lot of time teaching people how to write five-paragraph essays: one paragraph of introduction, three paragraphs of argument, one paragraph of conclusion. But outside the classroom the five-paragraph essay form is worse than useless: it's actively harmful.
For simple arguments, it's harmful because it forces the writer to jam words down the throat of their argument to plump it up so it fits the format. For complex arguments, it's harmful because it forces the writer to lop limbs off their argument to fit it into an arbitrary box. Most arguments are simple arguments, so the first sin is the greater one.
So much bad writing is bad because the writer couldn't just say what they mean and then stop. They stuff their argument with fluff like it's a damn pillow. An argument should be lean, cut, diamond-hard. Packing it with fluff just makes it soft and saggy. So skip all that -- just say what you mean, then stop.