I don't really see what you mean. The prefaces that the paragraph is referring to are almost always didactic literary criticism directly related to the work being discussed. It Was His Sled is a spoiler trope. The equivalent would be a Citizen Kane DVD starting up with a extended discussion about the sled before the movie actually starts.

Why not be more accurate? Not only does it go into more detail than anybody really might wish to hear about the sled, you also find yourself (should you actually read the preface first) wondering if a) the person watched this work b) while not high and c) how he managed to get the broomstick so deeply lodged without puncturing an intestine. In that order.

I *passed* english class and I'm bitter. Hell, I *aced* english class, and to this day I can swear to you it was nothing but a pretentous waste of time as well as money. I can see when there's meaning in work, and I can see when there isn't; sadly, that's pretty much the one most important skill that modern so-called "english" classes neglect to teach! People need to get a take a chill pill, get a goddamn grip, and realize that the hot dog that Joe Schmuckatelli eats in Chapter 3 isn't a metaphor for his latent hostility toward homosexuality, his decline from social prosperity, OR his return to appreciation of down home honest american values; IT'S JUST FOOD!