Novels are art. English teachers are not teaching you how to write as an art form. This is because our schools are designed to make good little worker bees. They are teaching you language so that you can then go on to learn technical writing. Now, I do think they should split the two apart, and let kids experiment and have fun with writing. That does not mean that they are wrong. Technical writing requires precision and a strict adherance to rules. It is the same concept as it being entirely fine to have a bit of fun when painting a mural, but not when you’ve been hired to paint someones house.