Again, you are the one requiring originating external justification for justice - you ask 'who made it', and without an answer to that question you consider justice unjustified, which itself is an oxymoron, and a problem that you and I do not share.
If we say 'the theory of evolution by natural selection is the theory that molecular mutations give either advantage or disadvantage to the survival of an organism' it is simply an explanation of the physical properties developing in species. Of course that does not adequately explain the concept of justice for you but then you are the person looking to the physical mechanics of the development of cells for justification for morality, which is in itself dependent on cognitive factors rather than strictly physical factors.
Guilt for a physical act exists. That is my position. We are beings of senses - sight, hearing, touching, smelling, tasting, all controlled by cognition, and a foul odour offends the senses much like a foul act offends them.
Tell me, without the knowledge of God, as a young child, would you find the image of a woman lying dead with severed limbs offensive? I would, and the reason for that is because I imagine myself in another human being's shoes.
Is it not justifiable to find atrocity offensive naturally? Or are only those who require an originating source for moral justification, morally justified? Is a young child for instance, not understanding God, unjustified in finding such scenery offensive? Of course not.
Morality does not come about naturally by following external rules and laws, morality comes naturally by observing a complex interdependent world of circumstance, cause and effect and asking questions of oneself. If an external source says to you, 'stone that woman to death, it is the moral law', do you simply agree with that command's moral validity or do you question it with your own empathetic sensibilities? Do you not ask, 'does the crime justify the punishment?' And 'is violence a solution to the problem?' And 'is the cause's effect the only viable outcome?' And 'can I take another human life?' And 'is stoning not painful?' And 'how would I feel in that woman's shoes?' And 'is there a solution that better remedies this situation?' And 'what good comes from stoning this woman?' You say you follow and inescapable, totally objective moral code, a deontological morality, but you don't really, because totally objective, universal commands don't exist for every situation a Christian finds themselves in, thus some Christians respond differently to certain circumstance than others. So even if a complete deontological moral code does exist, it is not in full effect nor in unanimous consensus. And I don't believe that it can be, certainly not presently.
Morality, at least for me, comes from mindful, observant examination of my motives, and from a sense that my own motives, thoughts and actions are the only motives, thoughts and actions which I am in full control of. My conclusion is, I will not stone the woman, because;
1. I am not her, and thus I have no right to decide over her life and death; I do not know her intentions, her thoughts, her circumstances, her conditions.
2. I would not like to be stoned. Stoning would be much worse than being a victim of adultery.
3. I do not think death can be a justifiable punishment for adultery, since to take life removes all possibility of life itself, which is just as important to her as it is to me, more-so than the ownership of my partner might be.
4. Stoning this woman is motivated by my own fear of consequence, not by compassion.
5. I have made mistakes in my life, and under different laws, I might also be stoned.
As for your last questions, about being 'the wrong side of morally wrong', that's an attitude of a person who looks for a condemnation or a sentence, not a person who looks for a compassionate outlook and holds forgiveness as a higher form of personally justifiable justice than duality and penalty.
I may be subject to the laws of my land, and I may be incarcerated for offending them, but I also have a personal choice to penalize others for offences against me, or to forgive them for offences against me. My personal justification for an empathetic, forgiving attitude toward those who have physically offended me stems from the realization that forgiveness towards others serves peace better than perpetual retribution.
There is no justification in my moral code for causing others to suffer because of that moral code. Harm, in our society, is synonymous with 'justice'. We say 'eye for eye', or at least 'finger for hand'. This harm is usually justified by saying either 'it deters others', 'punishment does not harm offenders, it reforms them', or 'harming offenders is good because it recompenses the crime'.
The first justification, 'it deters others', is essentially harming someone in the hope of changing the behaviour of someone else, but if harming someone truly deters others, then why does the country with the highest rates of incarceration, the USA, also continue to have one of the highest overall crime rates? And if it is because people are continually more violent, then surely incarcerating more people does not make the country less violent.
The second argument, 'harming others reforms them', is essentially harming a person into changing their own personality. If harming a prisoner changed their personality, then why does the country with the highest rates of incarceration, the USA, have one of the worst rates of recidivism? Prison is not reformatory in such a place, but rather it is dehumanizing - an exacerbation of wrong thought patterns, wrought with temptations, rather than a place for penitance and mindful examination of ones' crime and victims.
The third argument, 'harming offenders recompenses the crime' is blatant revenge based on a deontological perspective that says 'there is an absolute, equal moral law that God commands'. If that is the case, then surely God, who says 'revenge is mine' does not require our help to facilitate that objective, inescapable moral law.
There are just a few examples of why our 'sin, judgement, punishment' approach to legality, ethics, morality and justice is not only evidence of an utter failure to encourage perspectives that work toward our larger social vision for what humanity should be, but also a representation of our inability to recognize the breadth of our possibilities at all.
And that question, 'what should a human be', is one I consider better to ask than 'what external, originating, objecitve source do you have for your morality'. Look around you, man.