Isn't sin by definition offence against a God? The way I understand it christians see God as the ultimate authority. Like a father to a son. It makes sense given the fact that we are raised in an authocratic environment. I guess my point is when someone doesn't believe in the concept of God, good and evil as an authority is nonsensical. Eutyphro dillema and all that.

If you want to understand an atheist then you need to understand this first. If you mostly care for the carrot and sticks of your particular religion then I understand why you aren't motivated towards having a productive conversation.