Ok here's a scenerio for you:
FD decide to take up the suggestion to add the commodity "cannabis".
Along comes some sensational conservative news site notices this and writes an article: "Weed trading simulator" and the article somehow gains traction.
A potential buyer who has a negative attuide towards cannabis, views this article and decides (rather unfortunately) not to purchase the game because of the *perceived* negatively surrounding this aspect of the game.
This is all of course speculative, and please treat it as such.
People are probably going reply "I wouldn't want these narrow minded people in the community" true I would feel a similar point of view in this respect.
But that doesn't change the fact that's a potential sale lost, which is obviously not the best tactic for a company hoping to keep a broad buyerbase.
As ridiculous as this all sounds, it's not something that can be ruled out. I think sensationalist websites would have a much harder job writing the same article about alochol or tobacco.
Facepalm
There are lot of triple A games, and also lot of indie games, where drugs, commerce, use, and such, are essential parts of the game. And also, considering ED, the slave thing should be something wrong for you. So your point it's not a point.
as always, everybody should be smart enough to recognize that it's a videogame.