Ok first off you're referring to Seth. Secondly, that happened about two and a half years ago. Seth hasn't been a mod that long. Thirdly, that issue is well and truly over with.
By telling them they'll burn in hell :) ? That's not discussion, that's complaining because thir way of life conflicts with your religion, and you act like it's their fault that you get offended.
I have had several debates about religion with the subject only being mentioned tangentially...
One: Stop acting as if your religion has any more empirical evidence than someone else's.
Two: This is far more than just saying you disagree with someone because of Religion. The sentiments attached to "burn in hell" do not belong in a civilized debate :)
There is a difference between calmly expressing your opinion and saying someone deserves to suffer for all eternity. The passive-aggressive ":)" doesn't help, either.