I know little about this subject, but let me take the devil's advocate position. In that last example, how are teachers of English expected to teach writing styles, choice of words and phrases, language features and techniques or sentence forms if they can't analyse such choices in examples from literature?

I know there's a movement in artistic circles that denies intent in the artist, but some artists do actually have an intent. Art is used as a medium for communication and therefore can have meaningful content. It's important to their artistic expression. It seems to me that not all art is semiotically vacant. Is that therefore bad art? Should it not be studied in those terms?

I'm an outsider, I have zero artistic training or background so the chances I have any idea what I'm talking about are extremely low. The only reason I even know what semiotics means is because a flat mate of mine studied contemporary dance and I helped her with an essay on it once a long time ago, as English wasn't her first language.