Oooooh....
Playing hardball.
The obvious being that whatever the Constitution is silent on, falls to the States or the people respectively.
Hardball only in the sense of begging clarification for how the "Constitution" alone doesn't give the results those frequently citing it, perhaps wish it said.
Christianity is a big tent, and all parties therein do NOT agree on many things.
At the time of slavery, both sides invoked the Bible in support of their side's opposing positions. The abolitionists also invoked their interpretation of the intent of the Constitution. The pro-slavery side invoked "states' rights" to support their maltreatment of fellow human beings.
At this time, some invoke the Bible for their anti-gay rights side, since the Constitution is silent on the topic.
Since the Bible is NOT the law of the land, and the Constitution is, then we are left with our system of laws, through elected representatives and the courts, to settle difficult issues.
One solution would be to nationalize the bakeries (photographers, florists etc), and government could provide cakes for every purpose.
Bakers that refused to make gay cakes, could be sent first for reeducation, then to the Gulag.
The government cakes would be prohibitively expensive, and an underground system would come into being, to make affordable cakes, complete with "discrimination."