Kids read less and less. Assigning them works not likely to be absorbed properly and certainly not enjoyed is tantamount to souring them on reading permanently — something which has been done in many countries for way too long with teachers sticking to 'perennial' classics they (might have) loved, but which no longer enthuse. I stopped reading fiction for years after high school figuring literature just wasn't worth bothering with after get fed ponderous dribble and books not of interest to a young person. I only got back into reading after discovering Douglas Adams, and decades later read anything which grabs my interest, including Dickens and many other classic works.
A good teacher assigns works which lie just outside of the pupil's comfort zone, but not so far out there as to make reading a chore. Want to assign Dickens? Go ahead and read the Christmas Carol at this time of year; it's short and not too hard to grasp, and with enough hooks to go into Victorian society and other related topics. But assign David Copperfield? Great book, but for teenagers way too long for a work that old and removed. A teenager could read four novels that do connect with them in the same time. Sure, some teens might be ready for it, but it's not for everyone.
First, get them to read. Any book. Teach them that not all books will work for them. Skip that step, and you lose most of them as adult readers (the status quo by now).