This is a very strange question. I can't think of anyone who should not read The Alchemist, though many people may not like to read the style of the book. I can only think the question is something of a riddle meant to reveal that everyone (in someone's opinion) should read the book. I can think of three kinds of people who "should" not read this book. (1) One is the person who is not a seeker after truth, and who is going to admit they do not seek truth? (2) Another person is one who bores easily since the style of writing is antique sounding and simplistic in a fairy tale like way. Not many people have qualms today about confessing to being bored by the written word that takes more thought than a popular fiction or romance novel. (3) Another such person would be someone who scoffs at the existence of the spiritual realm since the message is a spiritual one.
But if you believe yourself worthy of the thing you fought so hard to get, then you become an instrument of God, you help the Soul of the World, and you understand why you are here. (The Alchemist, Introduction xv)