To really simplify the post-modern homosexual stance, wherein moral law has been turned on its head, view it thusly: "Thou shall not HURT my feelings" has become the redefined version of the First Commandment and the battle cry of the neo-morality crowd. For to "hurt their feelings" is the sin of being "not loving", and if you don't 'love' then you are guilty of being 'hateful.'
You said it. Funny, its been awhile since I've heard the term post-modern. I don't know if you have read any of CS Lewis's works. But he warns about post-modernism. I don't think that's the name he gives to it, but he saw its birth in his day. Perhaps it was starting out in England (and Europe) before it reached America.