It means what it says. Which part don't you understand?

"dull wasteland of neutrality" Being indifferent and no distinct in character is considered spiritually and intellectually barren .It is a boring state of mind lacking spirit! That is how a life without passion is described here.

你是英专生吧，这个是阅读教程上的么？我貌似学过。 Here, It means one's life should be full of passion, or it'll just like a wasteland being colorless. Passion adds color and hope to one's life.

If your life is without passion, it means you don't have interests, ambitions and dreams. Life without passion would be aimless, boring and not worth living.