I just had to post this.
The Bible doesn’t ever claim that the Christian doctrine of marriage is the same thing as the various kinds of domestic partnerships described under U.S. law. The Bible doesn’t say anything about marriage licenses and what partnerships the government may recognize. (Indeed, marriage licenses are a relatively recent invention. In fact, one of the reasons they became important in the USA was so that the government could prevent “mixing of the races.” They didn’t want churches marrying people of different “races” and so the marriage license was a handy way to enforce that racism.)
Perhaps Christians like Kim Davis would find it easier if English didn’t tend to use the same word, marriage, for both definitions. Christians have traditions associated with “Holy Matrimony” but marriage law is about equal rights under the U.S. legal system. Two different things. (In some countries, some people get married both in a religious ceremony at church and in a civil process at a government office. Other people simply get the government issued license and have a party.)