"...allowing them to refuse to people things to which they are legally entitled, such as marriage licenses, etc..."
That ship has sailed. The SCOTUS made it's ruling and it's over, DOMA is dead and buried. That pendulum isn't going to start swinging back the other way anytime soon. And to extend that metaphor, the best that those of us on the right can hope for at this point, is too keep it from swinging too far, or we'll have marriage licenses for Man and Irish Setter, or worse. Some people are already talking about defining the "rights" of AIs, and SkyNet isn't even self-aware yet.
Take heart, because your concerns really are unfounded.