The people who are horrified by the idea of children learning what they want to learn when they want to learn it have not accepted the very elementary psychological fact that people (all people, of every age) remember the things that are important to them - the things they need to know - and forget the rest.
Walt Whitman and Emerson are the poets who have given the world more than anyone else. Perhaps Whitman is not so widely read in England, but England never appreciates a poet until he is dead.