Different people get upset about all sorts of stimuli, from squirting blood to scraping nails to clicking computers to a microcosm inhabited by adorable inhuman sentients to whom no one gives proper moral consideration .

Actually, if I recall correctly, in the original Friendship is Optimal, once they were constructed, the non-uploaded people received the same moral consideration as those originally human. They were designed to fit into a preconceived world but they weren't slaves. I'm not quite sure whether that feels bad because it's actually bad or because it's so very different from our current methods of manufacturing minds (roll genetic dice, expose to local memes, hope for the best).