You are pretty much wrong about everything here, except I have always lived as a “majority” race. But I read, think, and talk to people, including a Chachtaw who has become a pretty good friend, but he is a lawyer so there is that.
Your first problem is that you see race and skin color as a “culture”. While I don’t deny that groups of people coalesce around skin color, the culture that might spring from that had nothing to do with race. The point is that in the US we can have a common culture that is comprised of people of various races. This is likely aspirational, but it should always be the goal.
Your second problem is that you, like many liberals, see world history as groups victims and victors. That is very Howard Zinn-like, so that might be what you are taught. While that is no doubt true in the sense that the world is largely shaped by war, you are flat dead wrong if you believe that the loser culture is lost to the winning culture. There is no better example of how wrong you are than the American West. Almost everything that is associated with our Western Culture is rooted in Spanish and Mexican culture. Spanish culture dominates everything you think of when you think of western culture. We do have the English system of law out here in Colorado (you do know what “Colorado” means, don’t you?) but most of what made up our history is largely Spanish. And Spanish is a native language in America, don’t let that slip by you. (We need to be bilingual in many places). In pockets in the West, native culture has blended with English and Spanish to form a common culture.* In South and Central America, we see blends of Spanish and Inca, Mayan, and Aztec, to form a common culture.
I agree America has always been seen as a place where people can excell with individual effort. I have written about that often here as I have said some liberal approaches to a heavily regulated society with ever expanding safety nets inhibits that. But the key is still a common culture, common goals, common objectives, and a common morality.
*Sadly there are those “multiculturalists” who want to rip apart the common culture we have built in favor of, well, segregated cultures.