The Subjectivity of Moral Values LIke I say, you're confusing descriptions with prescriptions. Moral rules, if there are any, are prescriptions. Now, can a machine issue a prescription? No, not literally. Someone can programme a machine to issue prescriptions, but then those prescriptions qualify as prescriptions only because we can trace them to a subject whose attitudes they express.
For example, imagine that meteorological conditions bring it about that the clouds above your head temporarily form into shapes that look to you like the words "buy some milk!" Are you being instructed to buy some milk? No, obviously not. Why? Because the clouds were not expressing the attitude of any subject - it was just a freak meteorological occurrence. We can describe why it happened by appealing to laws of nature - but those laws, note, are descriptive not prescriptive. Which is why explaining why it happened will not amount to showing that you were, in fact, being told to buy some milk. You were not being told to buy some milk and what appeared to you to be a prescription was no such thing at all, just some clouds.
Now, for it really to be the case that there is a prescription against being cruel, say - and there obviously is such a prescription, for virtually all of those possessed of reason recognise that there is - there would need to be a subject whose attitudes that prescription expresses.