(they are talking about this article)

"We can’t expect non-believers to live by Christian morals."

False. We can in fact expect non-believers to live by Christian morals. God's Word and Law are objective moral values. We have every place to expect even non-believers to live under such things. They are not just good for us, but good for everyone. The thing is that you can give reasons for His laws and morals being beneficial without just resorting to "because God said so." Those who seek to justify allowing sins to be legally and socially seen as okay are doing only that. God's Word is Truth, His Law is Moral. Human laws are to subscribe to His laws. Yes, we can choose not to. But it is WRONG to intentionally choose not to live by His laws.

"This is Not God's Nation"

Not a valid response. Whether it's God's Nation or not is irrelevant. Because it can be. Just because someone claims it isn't doesn't mean it isn't. Furthermore, if it actually isn't, then we should make it be God's Nation. Christians are NOT to back down from doing God's Will just because it's "not God's nation." That is not a good excuse.

"God doesn't honor a marriage license."

Yes, He does. A marriage license is a symbol of a promise. He will honor those that are made between consenting, unrelated adults of the opposite sex. And condemn those that are outside of True Marriage - His creation and ideal for the union between two unique humans that He created.