It is an interesting read, but I find myself wondering just how successful these games really are. There are two issues I see: the rules often emphasize the wrong aspects, and thus can be subverted; and the fact that games are often isomorphic to other games.
For the first issue, about emphasizing the wrong aspect, consider the description of the initial slavery games:
Brathwaite assembled a collection of tiny wooden figures, then had her daughter group them into "families." After her daughter was finished, she picked them up by the handful and placed them on a makeshift boat. Her daughter was confused: Why would she take the parents but leave the baby? Why wouldn't brothers stay with their sisters? "No one wants to go," Brathwaite explained. That's when it started to click.
Then Brathwaite devised a primitive resource management mechanic. It took 10 turns for the boat to cross the Atlantic. The boat had 30 units of food. Each turn, the player had to roll a d6, and reduce their food stores by that number. By the trip's halfway point, it was clear to her daughter that her "cargo" wouldn't make it. It wasn't a "fun" game by any means, but it served a different purpose: It helped her daughter intuitively understand the emotional experience of the slave trade, a lesson that numbers on a chalkboard couldn't provide.
In the first example, what if the player made a conscious attempt to keep families together? Doing that defeats the moral lesson that you are trying to teach. Or in the second, suppose the player figured out the right balance between slaves and food stores such that she could keep the "cargo" alive till the end of the journey? Is that winning? Or would it teach that slavery is okay if you take proper care of the slaves?
If you change the rules of the game such that it is impossible to survive the trip, does that show that slavery is evil, or does it really show that you rigged the game to ensure the "right" outcome?
The rules of a game can simulate many things. However, I'm not sure they can get across fundamental moral points like the idea that it is wrong for one human to own another.
The second concern is that game rules can be thought of as just problems that can be solved. Such problems are often isomorphic to different problems. That means the underlying rules, constraints, and solutions are the same, but the context is what determines the morality.
For example, consider the game Train described in the article:
The object of Train is to get a collection of people from Point A to Point B by placing them in a boxcar and sending them on their merry way. Played among a group of three people, players draw cards from a pile that can impede other players or free them from existing obstacles. The first player to reach the end of the line wins.
The destination? Auschwitz.
Now, the article doesn't really expand on this, but the underlying problem is a logistics problem like the ones faced by airline, trucking and other transportation companies every day. The shock comes from the context: that the people being transported are Jews and the destination is a death camp. The context is very important, but I don't see what the *game* part actually adds.
Or let's look at the second slavery example again:
Then Brathwaite devised a primitive resource management mechanic. It took 10 turns for the boat to cross the Atlantic. The boat had 30 units of food. Each turn, the player had to roll a d6, and reduce their food stores by that number. By the trip's halfway point, it was clear to her daughter that her "cargo" wouldn't make it.
Let's change the context. Instead of slaves, let's say the boat contains refugees fleeing a city that is being destroyed. As they cross the ocean, they realize that they don't have enough food for everyone to survive. Now the lesson the game teaches is about hard choices, and maybe even about the nobility of sacrifice. It's diametrically opposite from the evil of slavery, but the underlying game mechanics are identical in both cases.
The context, or the "fluff", determines morality, not the game rules. But if you're using a game to teach the moral concept, and someone sees through the game to the underlying isomorphism, that weakens the lesson. It makes it easier to declare the two situations equal, to justify actions taken.
Games are problems where you need to find a solution while being bound by rules and constraints. These rules and constraints are the most important parts, more important than the context that surrounds them. As such, games are a poor medium for conveying lessons about morality and social problems. Rather than focusing on the moral issue, the game becomes about trying to achieve an acceptable outcome by outwitting the rules.