Let's take a reality check and compare the following similar scenarios: Mahmoud Ahmadinejad, current president of the Islamic Republic of Iran, is (in)famous for denying the Holocaust. In his world it never happened. The rest of civilization is outraged at his sheer ignorance and defiance of true historical facts. I haven't read any Iranian school history textbook, but his verbose utterances at any given opportunity and shameless indoctrination are probably more than what most Iranian children will learn from their textbooks proper.
Another example: The former GDR (German Democratic Republic) in their history books, for about 30 years, denied any involvement with Nazi Germany until their collapse in 1989. Au contraire, everybody in that part of the former Third Reich had been an anti-Nazi freedom fighter all along, oh yes, was never a party member, and anti Hitler. Only the post-reunification generations have been learning about the fact that their forefathers were participants and also cannon fodder of the regime just like people in the west.
May I suggest whitewashing slavery with an equally favorable brush or the tragic genocide of Native Indians for future school-board consideration? For me as a European, they don't look so good in America's history either and need beautifying.
We cannot let it pass as a form of Humpty-Dumptying - as in Carroll's"Through the Looking Glass":
"When I use a word, it means just that what I choose it to mean- neither more nor less".