The context is that unless we believe scripture reveals clear guidance directly dictated by God on every possible moral issue, we cannot say with any certainty that we know what God wants us to do apart from follow our conscience to the best of our ability.
Religions don’t agree on knowable objective moral values, and so there is no prima facie case that any given religion’s ethics are automatically superior to any others or to purely secular ethics. In that sense the state could even transcend religions to produce a new synthesis. For example, the first preamble of the secular
UDHR “Whereas recognition of the inherent dignity and of the equal and inalienable rights of all members of the human family is the foundation of freedom, justice and peace in the world” can also be found, rather more poetically, in Psalm 133: “How good and pleasant it is when God’s people live together in unity! It is like precious oil poured on the head, running down on the beard, running down on Aaron’s beard, down on the collar of his robe. It is as if the dew of Hermon were falling on Mount Zion. For there the LORD bestows his blessing, even life forevermore.”
In both cases we have an exhortation to brotherly love for its own sake, or as UDHR Article 1 has it: “All human beings are born free and equal in dignity and rights. They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood”. Gay rights can be argued direct from that aspiration.