The question is corrective feedback, not merely correction. The objective of writing instruction, which is not the same as promoting writing, is to help every young writer get better every day, on terms that every young writer can understand. We know what bad writing is, and so do young writers, just as we know bad music.
People know bad writing because they have to study to understand.
That is very different from good writing which people follow by interacting with ideas and images from the writer. If we don't teach those kinds of things, from their work, they don't learn them, and the probability that they become good writers is compromised. Merely writing a lot has been shown clearly over the last 25 years not to be sufficient. The objective of writing instruction, which is not the same as promoting writing, is to help every young writer get better every day, on terms that every young writer can understand. We know what bad writing is, and so do young writers, just as we know bad music.