While I agree with you on the larger point, the biblical excuse for anti miscegenation laws, which were on the books in places like SC into the 2000s, is not from Leviticus but from Paul's Epistle to the Galatians, or at least that's what modern preachers have used as their rationale.
Edit: No, I'm wrong. The constitutional amendment in SC was 1998 (a friend of mine was one of the few in his precinct who voted in favor, that's why I remember the Galatians thing) and Alabama was 2000.