I don't have any information to counter your claim that 4j students are reading "The Giver". I did look up the book and found it is often an assignment for middle school students across the nation and it has won literary awards. But let's look at your claim.
First, to say 4j middle school students are reading it does not quantify how many are reading it. All of them? Half? A few? Is the book assigned? Is it an option? Can parents op out? 
You cite one specific part of one chapter. What is in the other chapters? Sure, some could claim nothing makes up for that one chapter.  But without knowing what the whole book is about, that is a narrow slice of it's contents. 
When people just accept what they read or hear and then get upset over it, it's no wonder they have a negative view of things. Here is some background on the book: https://en.wikipedia.org/wiki/The_Giver#Literary_significance_and_criticism