It means it's easy to destroy a boy. Just whisper in your ear, there is no Diga Altman in this world, which is very similar to the meaning again and again: Ye Qingjie means to break the dream of a simple middle school teenager and see the reality clearly. It's like telling a boy who firmly believes in Altman's existence that there is no Diga Altman in this world, breaking the last glimmer of hope.