Was the book unbalanced, though? When did you read it?
Does it matter if the book is one-sided? Not to the people so angered by the thought of parents having input in what books their children are required to read. From your link:
"She clarified and said that she felt that we needed the perspective of the American government, and why Japanese internment happened," Zielke added. "And so then again, we had raised voices at this point. I told her specifically, I said, 'The other side is racism.'"
There you go. You don't get a side, because we have predetermined that any opinion other than our own is racism.
Does the book mention that the people who pushed for and benefitted from the incarceration of these Americans were California Democrats? That the president who supported it was a New York Democrat?
Let me guess: yet another text book that decries all Americans as racist without bothering to mention that the racism was almost entirely perpetuated by one party, the Democratic Party?
If you don't know what the Democratic Party is, being from some other country, my apologies.