This may be pedantic, but I think it’s something worth acknowledging. Whenever there’s a social issue of any variety (racism, homophobia, locking children in cages, etc.) there’s an impulse by some to proclaim, “This is not who we are! This is not what America is about!” Inevitably this will be followed by someone else pointing out that these social issues have actually long existed in the United States.
Both attitudes are correct, of course. The second person is right – we should not erase the brutal aspects of history. The first person is also right, but perhaps phrases their position incorrectly; I’d suggest, “This is not who we should be! This is not what the United States should be about.”
These two positions are not mutually exclusive. Instead of working against one another, they should work with each other toward their common goal.