Do we give them the opportunity to learn a new way? If I never knew how "act like a human" (what does that mean exactly? Who decides?) why am I punished for what I did not know?
See, the examples that you point out in our world make it challenging because we know the systems are in place to teach morals, right and wrong. Germany was the seat of many Enlightment figures, and philosophers, but also had their own struggles. Are those figures present in the Mirror Universe? Did they have the same moral philosophy to teach them these things that we now take for granted? Is right and wrong a moral absolute across universes? If so, what is the standard and who arbitrates it?