If this many people missed it, it might have been the way it was written was ambiguous or something.

Nope. People "miss" obvious descriptions of race all the time. Which is why there was such a shitstorm when the Hunger Games movie came out and people were shocked that Rue was black, even though her skin color is explicitly described when she's introduced in the book.

Another book I like has a character described as having black skin -- those exact words -- and the author said that she got tons of questions from readers asking her if she meant "hair." Because it's so easy to typo "hair" as "skin." The keys are like right next to each other.