I think terminally online people and their kids probably know mostly the truth (or closer to it) than the average American. The fact that one major political party in America is having pretty major success pushing whitewashed history or at least preventing they're history from being taught strongly undercuts your contention that "we talk about our atrocities all the time."

If it was some fringe group like the John Birch Society or some Ayn Rand cult, sure. But it's almost every Republican primary candidate.