Moral situations only emerge from interactions, but not all interactions imply moral situations. There are varying degrees of interactions from bumping into someone on the street to simple agreements, to formal contracts. Laws, for example, are not moral systems, they are imperfect social contracts in an attempt to capture objective moral realities.
If agreed upon contracts, even at a social level, aren’t attached to objective moral realities, then they don’t really exist in the sphere of a moral system... they are just agreements and contracts. How does one know whether they are acting from an objective moral reality as opposed to merely an amoral agreement or contract? Here’s were it gets real simple and has already been expressed very efficiently:
Do unto others as you would have them do unto you, and Confusius’ addendum.... do not ask others to do for you what you would not do for yourself. These moral observations are alluding to the very furnace of moral objectivity - the potential of personal and real violations of the self that are beyond mere agreements and social contracts.