It is one of the basic Enlightenment beliefs of the USA, that all people are equal before the law.
That is a moral statement.
Science cannot decide who is "superior," because Science uses evidence and logic without judgment.
And deciding whether one person is superior to another, or not, is a judgment.
Now, you might say that White people are better at synthesizing Vitamin D in their skin when exposed to sunlight. Or that Black people are better at withstanding sunlight without getting a sunburn. Even that is a matter of averages; I have known a Black child who got sunburned much more easily than my fair-skinned daughter. I was surprised, but it is true. So I don't know which of them is better at making Vitamin D, as I don't know how to measure that at home.
You can choose whatever traits you prefer in a person; but the Law cannot.