This is not a criticism Old World, but I still consider that a kind of sanitizing, because pre-modern societies didn’t make a “value judgement” in terms of advantages and disadvantages when choosing to engage in slavery. It makes sense as a mechanic, but not as history. It’s a very complex topic, obviously, but slavery existed in some form in pretty much every pre-modern agricultural society on earth because it was far more economically viable than the alternatives (even where “forbidden” it was often replaced by systems only marginally removed from it).
I like the acoup blog’s point on humanizing history and I’d love to see more of that. But I don’t see a big problem with games designing mechanics for gameplay reasons - as long as the creator is aware. The main problem I have with questionable mechanics and the “just a game” argument is when it’s either in massively bad taste (and that will vary from person to person, obviously) or when the designer starts arguing for historical fidelity as justification for their interpretation.
Honestly, I think a lot of issues would be avoided if designers/creators would make sure they have basic broad knowledge and stop trying to play the historical fidelity card when faced with criticism.