Slavery was also a cultural say of life in America many places all over the world. There were probably secondary effects. But that doesn't matter because the practice is and always was, objectively evil.
How can you justify discrimination based on somebody's origin in any modern society? What kind of negative "secondary effects" that anti-discrimination would bring to a society? It's not like this is a small country or the first time we're talking about this issue.
I do, however, want to be sensitive to the fact that it may have some secondary effects that I'm not aware of, having never experienced firsthand.