You'll find opposition to mixed-race marriage is pretty common on the black and Asian sides. For as much as the left pretends that whites are sooo racist, they haven't displayed the same sort of in-group tribalisms that every other race does for going on half a century now. You might find some especially old white folks who still complain about it, but you'll find plenty of blacks and Asians in their 20's who will strongly and proudly voice their opposition to members of their "group" being in mixed relationships, particularly with a white person.