The textbooks and the mainstream media in all places tend to play the "nationalism" card; that's self-serving in all sorts of ways, after all. And no one articulated the 'nationalism' caricature better than George Orwell: "The nationalist not only does not disapprove of atrocities committed by his own side, but he has a remarkable capacity for not even hearing about them."
This varies by textbook. The textbook went to High School with (The American Pageant & New York State in 2003-2008) definitely talked about this and they had a photograph[1] from the massacre.
Your point about the influence of textbooks is rather important though. Putting aside the fact that many people just don't pay attention in history class, the default narrative that is being taught is quite varying. If I owned a house rather than just renting one, I would be starting a collection of High School history textbooks for this reason.
