That is not exactly true... it is the current narrative. Racial oppression existed throughout the world. At the same time, Europeans had black slaves, over 1.5 million European slaves existed in North Africa, even more Russian slaves were prevalent in Central Asia and the Middle East was filled with slaves taken from the Balkans. Native Americans regularly took slaves and happily participated in the practice not only in North America, but South America.
If you want an honest discussion of the history of racial and ethnic oppression, you must begin with the reality that it was not some unique practice invented by Europeans, but rather historical records show the practice dating back to before 4000BC based on some Egyptian writings. Now that we agree everyone was guilty of slavery. Concurrent with that is the history to end racial discrimination and ethnic discrimination.
The abolitionist movement began in Europe and grew out of the ideas first expressed in the Reformation and later began to find greater expression during the Age of Enlightenment. Beginning with outlawing slavery in Europe, the movement spread to all the European colonies. Eventually, the US, Britian, and France united to try to end the practice globally with mixed success, since human slavery continues to exist in the world.
What is really interesting America emerged as the most powerful nation on the world, not through its military and economic might (though those were the expressions of its power). What made the US the most powerful nation in the world was its unique "anti-racist/ethnic" ideology. This ideology did not happen overnight... but over its history... America extended citizenship to every citizen born within its borders with the 14th Amendment.
To be even more inclusive it extended to the original people of North America the unique right to have dual citizenship though this took until 1924 to happen, prior to that a person could not have both tribal and US citizenship.
America remains one the few nations extending citizenship rights to anyone of any race born in America. This radical idea was conceived of before America became a country and remain incomplete but serves as an aspirational goal.
So, while it is true America has never been perfect, more than any other nation on earth, it has aspired to unifying people of all races, religions, and ethnicities into one people, something that as you know not even the original tribes offer...
However, I think the first step in drawing people together is to understand the history of their own people when it comes to oppression. That helps them to understand where the Europeans were coming from initially and how far we as Americans comprised of all races have come. Have you studied the history of oppression among the tribes of North and South America including slavery?
https://en.wikipedia.org/wiki/Slavery_among_Native_Americans_in_the_United_States
