I saw the comment that god is the only one that can bring real justice and I agree with that but why would a loving god punish people, I would assume death would be punishment enough... But those are just my views on the matter.
On thing, if there is no afterlife, and yes there may not be, though I do have faith. No afterlife, then there is no justice in point of fact. If no afterlife, then we live in a world were 'evil' wins out. There can be no balance and the desire that humans have for justice will go forever unaswered.
If morality is truly subjective, then it does not matter what we do in reality.....the only consequence is getting caught. To kill or love is equal, it depends on what one desires to do. I don't believe that of course. We are commanded to love one another because it is in fact hard to do, perhaps impossible without grace. By love I mean to love those truly "other".
As my friend doug likes to state: "If I have a conversation with a humanist and he gives me his take on morality, I may agree with him, but what if I don't(?)......good and evil is subjective".