The portion after the title can be clearly read as: "Why are middle class blacks angry? Why should America care?" The Goodreads website title's version is not only incorrect, but poorly written and spelled.
There are also three versions of the same book, two without cover art.
It appears that the book was originally published with the subtitle "Why Do Prosperous Blacks Still Have the Blues?", or at least it shows up that way online, including at Harper Collins, though I doubt the misspelling "Prosperouse" (which is in every online source I've seen) was on the actual book. Goodreads doubtless just imported that information from Amazon or wherever. The book's title according to Library of Congress is just "The Rage of a Privileged Class" and perhaps it would be best to leave it at that.
There are also three versions of the same book, two without cover art.
Thank you.