It is not outdated yet. After the marriage is fait accompli and there are children the stigma rapidly fades, in part because the children (if the Indian mate is dark) raise the apparent caste level of the family by being lighter skinned. I am long acquainted with several such families. The strong distaste for the foreign choice disappears soon after the marriage, especially if the marriage is a possible a ticket to emigration for relatives. The light-skin preference does not really work across cultural lines. When such lines are crossed the affluence of the foreign culture(and the individual prospective mate) is the dominant consideration. That works for third world Orientals marrying American Negroes. Any stigma is formalistic and quickly dispensed with and is the same as that for marrying a Nordic-American.
They cannot raise the “caste level” by the pigmentation of the offspring. In fact, marrying a foreigner is the quickest way to lower oneself in the racist caste heirarcy.
It is for this reason that Anglo-Indians were accorded special protection by the Indian constitution.