What "race"? The human race has evolved into gene pools with different skin tones, and tendencies to other different physical nuances.
For a myriad of reasons, it's common for those differences to correlate with cultural differences.
It's naive, so un-diplomatic that it's dangerous, and utimately disrespectful, to try to ignore those cultural differences, let alone play "my culture is better than your culture".
Perhaps the best thing about "interracial" marriage is simply that more people are not eliminating possible partners for invalid reasons, and less people are ostricizing "mixed" couples for such reasons.
As to "who's beautiful", I'll confess to taking a measure of delight in what is so far the less commonplace; but I hope I'm not ass enough to actually make either "purity" or admixture a measure of worth or an actual "standard" for beauty.
Our baby nephew is your basic white kid. Our baby neice has a white parent and a decidely black parent. Either one of the little critters just melts me down in my socks.
(Wonder if I'll find I've made some of the people angry, or all of the people angry?)             Dean