Obviously the real racists are the couple who complained

If you are a clergyman, you can pick and chose the people for whom you are willing to perform wedding ceremonies. If a couple comes to you and you don't think they should get married you are well within your right to refuse to perform the service or give the couple the blessing of your church, temple, mosque, shrine, coven or soltice circle. Catholics are under no obligation to allow gays or non-Catholics to marry in their church. Orthodox Rabbis can refuse to marry goyim. Druids can decline invitations to sanctify the handfasting of one of their congregation to a Republican. Churches are private organizations and can do what ever they want as long as it doesn't involve human sacrifice or annoying me in my home.
Government officials do not have that luxury. If someone meets the legal criteria for marrying - that is to say, they are of legal age and not obviously insane or under duress or siblings - you have to give them the licence, no matter what your personal feelings are.
So this dimwitted clown doesn't have a leg to stand on when he tries to defend his refusal to grant marriage licences to interracial couples. He should not be allowed to resign, he should be removed from office, yesterday. Naturally though, he claims not to be a racist, he's just thinking of the children:

However, [Justice of the Peace for Tangipahoa Parish’s 8th Ward Keith] Bardwell told the Hammond’s Daily Star that he was concerned for the children who may be born of the relationship and that, in his experience, most interracial marriages don’t last.
“I’m not a racist,” Bardwell told the newspaper. “I do ceremonies for black couples right here in my house. My main concern is for the children.” Bardwell, stressing he couldn’t personally endorse the marriage, referred the couple to another justice of the peace.

Yes, I'm quite sure he has nothing against black people, he even allows them into his very own home. I'm sure he has a vast collection of Fats Domino records and thinks Tiger Woods is a credit to his people, some of his best friends yadda yadda yadda...

Which, of course is all bullshit. He is refusing to comply with the law and denying people a civil right on the basis of race. Despite his protestations to the contrary, this makes Justice of the Peace Crackerpants McCracker a racist.
I'm sure 200 years ago his ancestors were singing the same song - They were not racists, but they just could not support abolition because "what would happen to the poor children of the freed slaves without a white master to look out them? why they'd probably start stealing watermelons and the next thing they'd want to learn to read and before you knew it they'd be leering a white women and then where would they be? No, slavery was the only way to ensure those poor children didn't go wrong and get uppity and get themselves in trouble."
"Its for their own good," they'd say.

Bardwell's concern for the children of interracial couples is actually very touching, since the offspring of such relationships so often go wrong.