But just offering the book, without forcing them to read it, is not imposing one's values on kids. What the parents are doing, forbidding the kids from reading it, is imposing their (not the kids'!) values. They're not equivalent.
IMO the non-zero-sum solution is exactly where neither group imposes their values on the kids, i.e. making the book available for those who want to read it (which will have to mean available for all of them, since we can't know in advance which of them will want to), without either making it mandatory to read or forbidding them from reading it.
Seems to me one of the sides of this issue is a lot closer to that ideal than the other.
IMO the non-zero-sum solution is exactly where neither group imposes their values on the kids, i.e. making the book available for those who want to read it (which will have to mean available for all of them, since we can't know in advance which of them will want to), without either making it mandatory to read or forbidding them from reading it.
Seems to me one of the sides of this issue is a lot closer to that ideal than the other.