Yes diversity is a good thing, and the more diverse we are the better, (at least emotionally, but I don't have any empirical metrics to back up if diversity is better for everyone in different societies?), but excluding someone based on the color of their skin is racist. It's as simple as that.
The only difference between you and me is that I don't give two shits what the color/age/gender the SCJ is, it is only you who want to discriminate based on these things, and at the end of the day, that's being racist.
Having said that, we all know that this Administration wouldn't nominate anyone other than a white dude as a SCJ, and that is equally as racist.