I fully approve of strict reading!
So, I see now that you are being very narrow in what you mean by justice: it's an agreement (necessary, but not sufficient), but not just any agreement; it's specifically an agreement not to harm.
I can work with that definition for the sake of pursuing this discussion. As per one of my previous comments, I don't think that invalidates any of my arguments.
I would personally go further, to say that it's unjust to violate ANY of our explicit agreements (not merely to withdraw from them - but to deliberately violate), but I can see where some might object, and I don't think it's a terribly important point right now.