There are three parts to why high school students hate reading.
First, most of them are stupid. Plain and simple.
Second, the books that high school English classes make us read are crap. (Lord of the Flies, anything by Jon Steinbeck, and the goddamned Handmaid's Tale)
Third, and most importantly, school excels at making learning a boring endeavor. It is a tragedy what they did to history, the most badass of intellectual disciplines. They do the same with English classes; even if high schools do allow a good book to be read in an English class, they require so much redundant talk about "symbolism" and endless essays on the text that it becomes a chore to read, not a privilege.