I learned that Rue was black from reading the book because I paid attention. I didn't have to pay any particular attention, because when I read, I try to let the author tell me who's who rather than to read with the presumption that all of the characters are white. That may not be true of ALL Americans, but it is certainly true for MOST Americans.

My entire point was that people read the book through the lens of their "centeredness," if I may, and were, therefore, offended when Rue turned out to be something other than what they imagined.

I'm looking at this through two viewpoints. The first is that there are always going to be white people who are upset that any character is black. The second is that even when given explicit language by the author that identifies a character, there are still those readers who envision the character as white. Then, having found out differently, they are angry at themselves for "feeling sorry" for a character who didn't look like them. And remember, this is fiction!