Let me tell you right now that this kind of thing doesn't happen very often to me. For everyone who likes one of my books, there's someone else who hated it. This particular title is the one that really polarizes people.
The big idea in The Last Song of the Swan is how we determine who is "US" and how we exclude those who aren't. The story is a dual narrative. One thread takes place in Albuquerque a decade ago. The other thread takes place in what is now Denmark during the last Ice Age. Despite the differences in place and time, the question of who belongs and who doesn't remains the same.
But this ugliness is not new. I was teaching English as a Second Language back in 2011 when Osama bin Laden was killed. and the wave of patriotism that swept the nation also swept my school. Some of that wave was lovely. Other aspects were not. Some of my students received nasty anonymous notes in their lockers, telling them to go home. Some got spat on in the halls. The crazy thing is, not all of these students were even Arabic or Muslim. They just looked different, foreign and were therefore part of them and not included in us.
The good news in this study was that children who saw lots of different faces very early in life did not have as big an ORE response. But by early, the study meant really early. If we want children to not grow up with racist tendencies, we must lay the building blocks long before they learn about King's I Have a Dream speech in kindergarten or even learn the word equality.