That is an example where divisions can be healthy. However, as we see in the current U.S. political climate, division can be dangerous and destructive. I can't remember a Presidential election that wasn't pressing, but the stakes for this current one seems exceptionally high. Divisions contribute to this.
When we look at groups of people through an "us vs. them" lens, we often feel threatened or antagonistic. Fellow humans become them who want to take our property or opportunities. When we view refugees fleeing the destruction of war as terrorists, we sink to our lowest capacity, that of frightened animals. There's a difference between caution and callousness, between wariness and hatred.
America has a massive racial and discrimination problem. I don't think that repairing our racially divided past will come from eliminating our differences, whatever that would look like (a monochrome American culture?). Besides, who would want that?
Rather, it's only by recognizing our differences, while simultaneously viewing our fellow men and women as brothers and sisters, that we can hope to forge a new future for all Americans. Of course the experience of black Americans is different from mine as a white American. The same can be said about any subcategory of America--be it based on gender, sexuality, religion, and so on.
I don't need to erase my culture or anyone else's in order to fight for equality. I find that's it more helpful to look at the plight of marginalized Americans this way:
How can we as Americans fight for equality for our black, transgender, homosexual, female, Latino, Muslim...brothers and sisters?
This perspective recognizes differences (my foot is not my arm and my heart is not my kidney) without allowing those differences to divide. That's the goal--and in my opinion, the true function--of any spiritual tradition, especially Buddhism.