Learn your history. The colonial governments of Spain, Portugal and France actually granted legal rights to those they conquered, encouraged assimilation and had no problem with intermarriage. It was the English (and their descendants) who pushed anti-miscegenation laws in the New World, whether in America, Asia, or Africa.
Islam is a religion, not a race. Therefore it cannot possibly be racist to oppose the mass immigration of Muslims to Europe. The growth of militant Islam in Europe is certainly not a good thing from a Catholic point of view, and those earlier Catholic regimes would not have allowed it.
As for immigration in general, the real root of the problem is that Europeans, having rejected Catholic morality, are not having enough children to replace themselves. Therefore their civilization is in danger of dying out. It can hardly be un-Catholic to oppose this.
If Europe's population becomes dominated by "Indians and Asians," whatever their religion, the continent and its culture will no longer be European or Western in any meaningful sense. It will simply be an extension of Asian civilization. I have nothing against Asian culture; I simply want European culture to survive too. What's wrong with that? There is nothing in Catholic doctrine that requires civilizations to dissolve themselves in the name of multiculturalism.