@Sigismund,
Certainly race is among the most difficult and often treacherous topics so it's hard to make our vocabulary about race as clear as we might like. Yet saying that race is highly relevant isn't the same as saying that biology determines all. Race is a vital gift of God, but not God Himself. And as Catholics we view the human body as something essentially spiritual in nature, and only secondarily material, so naturally by race we mean something also spiritual, not anything crassly material like the Darwinists believe.
Since we're talking about compassion among European white folk, I should clarify that in "race" (a SPIRITUAL phenomena) language is a greater and more powerful factor than genetics. No doubt genetics is the most stubborn aspect of race because the most material, but "race" must also fully include more fluid and easily improved factors like language as well. So when we care about our own race, we're also talking about caring about improving the more spiritual factors of our fellow European Catholics (and Protestants) like education, language, manners, customs and the like. Not just talking about the most intractable and most material racial factor of genetics alone. Racial genetics tends to be the more vulnerable racial aspect most in need of protection and defending (especially against selfish miscegenation), but the other milder racial aspects also need to be promoted and cultivated just as much as genetics.
Again, human races aren't just genetics alone as if we were talking about cattle breeding. The relevance of our human racial heritage is mostly about how our human civilization is passed on over the generations through filial piety to our ancestors and their holy Catholic religion. We normally honor our parents by gratefully honoring the spiritual racial inheritance we have received from them and as incarnate human beings this racial heritage must include both the more intractable material genetics of our bodies as well as our minds that require the languages and civilization we have also inherited from our parental ancestors. All of these things together form our racial heritage, at least as Catholics have normally understood this difficult topic.
Please don't always hear "Darwin" whenever a Catholic mentions race. Darwin does not enjoy any monopoly over racial topics and Catholics have a vast history about how we understand race that has nothing to do with that disreputable Englishman. In general we see Romanity as the natural basis of our history and civilization with a clearly white European core and impetus, but we also see our racial heritage as such a uniquely generous and noble human (and therefore racial) civilization that we also welcome other non-European races to join us in the joys of our European Romanity. And we feel a very strong responsibility to help and respect the part-white races even more because they also have a much closer natural connection with us.
Our Catholic charity builds on nature and grace perfects nature, but neither charity nor grace can do anything to help human beings who imagine that they are so angelic that they are altogether too good to have any connections with the material world. If the material aspects of human bodies like genetics mean nothing to us then we probably can't have any real charity or compassion for our fellow human beings. Our human race has a very real and material hierarchy of human genetics (as well as of languages, civilizations and, above all, religions) and it is only to be expected that the best religion (Catholicism) naturally emphasises ALL the best and most superior aspects of the human race.
As Europe is geographically the most pleasant and beautiful continent of the world, as Rome (or Europe) is the most superior and joyful civilization in the world, so naturally it is only sensible that the white European genetics of ours has been at the biological core of Catholicism because it is also the best genetics on earth. Would Our Lord fail to make his own everything that is best? Therefore our entire racial heritage, including our languages, manners, genetics and religion, are ALL of them quite naturally and rightly simply THE BEST.
Humility isn't disdaining the created hierarchic human race in favour of an imaginary humanity of egalitarian interchangeable cogs in a machine that don't and can't exist. Humility for white European Catholics begins with GRATITUDE to the Good Lord for all the ways in which He has blessed us and made us the pinnacle and envy of our entire human species. (The Catholics are the most envied and hated by the Jews BECAUSE the Catholics are usually the best. If not then the Jews wouldn't envy and hate us.) Along with gratitude for God's religion that blesses our souls, we should also be grateful to our God and ancestors for our human bodies together with the many other temporal gifts of Romanity and therefore grateful for our white European ROMAN RACE!
And then we can begin to have more genuine humility towards our white European selves and charity towards our fellow European white folk. Because charity begins with humble gratitude.
P.S.: Of course miscegenation isn't ALWAYS wrong and its illegality is something for the CATHOLIC STATE to enforce, not the Catholic Church. Still, what our Catholic State and the Old Testament have always rigidly forbidden by force of law is also something gravely sinful. Not ALWAYS, but surely at least NORMALLY with only few exceptions.