What slavery was doing, from an industrial and economic standpoint was wonderful for the owners, and very hard to quit - all of the objections to it were moral. I.e. "it's great apart from that pesky little detail where it's horrifically evil."
Quite a few antebellum churches desperately tried to plaster over this extreme cognitive dissonance between their teachings, and the practice of their society. You can find plenty of published material to that effect, but all of it has the same sort of flavor as Orwell's "some animals are more equal than others", wherein it has to somehow invalidate all of their core ideological principles, generally without a logically rigorous reason. ("All humans are equal" -> "well, what about them?" -> "oh well, uh, they're not really human" -> "because?" -> "reasons." )
I understand where you are coming from, I struggle with my atheism/beliefs too.
But without doubt, this is good for society. Think about it, we had slavery because bible and other religions, approved of slavery. Then women had no rights because of religion, finally they do. These are good things. I believe homosexuality is next big step for humanity. Once this is accepted, no one would even think about questioning it.
As for old old family values, I am not really sure what it means, but if it means close family ties, then I have seen non-religious families who are very close and religious families who fight all the time. And vice versa.