I am unaware of any theology that is against interracial marriage, so I would consider such a claim to be ersatz. As to the other two examples, I would have the same attitudes.
1. "If the white man who belongs to the chosen seed mixes his blood with the seed of Cain, the penalty, under the law of God, is death on the spot. This will always be so." -- Brigham Young
2. How did Bob Jones University defend its ban on interracial dating?
Neither of these are currently in force, which goes to show much "deeply felt religious objections" tend to track with the culture as a whole rather than absolute theology.