Most countries founded on invasion and genocide don't want to think about the victims, or acknowledge they had a 'real' civilization. Especially when their nationalism and Constitution-worship glorifies the genociders.
You're being downvoted, but I don't think you're that wide of the mark. I think what's at issue in the U.S. is the proximity of the genocidal acts (as well as the ongoing racism) and the social consequences of honestly addressing them. Italians today don't care about the consequences of Carthage because it's so far in the past as to almost seem fictional. But if you take a more proximate example - say, the Armenian genocide in Turkey - you find a similar phenomenon of widespread denial and/or ignorance.
You d be hard pressed to find ANY country not based on invasion and genocide. Even China which was never fully invaded has a long history of civil wars and genocides to unite the different regions or keep them united.
wtf, anyplace with an "ancient" anything anywhere in the world is almost guaranteed to have been the victim or aggressor of an invasion at some point in history. go read some world history books.
But hey, at least the one in the article is thought to be Objectively Not Our Fault, having collapsed pre-Columbus.
But notice how the entire angle of the article is Our Fault (well, your fault, I'm not American). That's what people want to hear nowadays. So the fact that it is "objectively not our fault", as you say, is actually a liability.