I think bringing up about town size and segregation is not really applicable logic here, because DF is bringing simulated world into smaller scale, simply for better gameplay and simplicity.
Another thing we have to consider is, these kind of cultural and societal details won't be applied to DF before 5-10 years. So it takes lot of time till we actually get there. And since this topic is heavily loaded with political beliefs, i'd say we don't even know what kind of political climate we stand in 10 years, since at the moment one of the arguments against applying this type of game mechanic is mostly/also political one. Looking at current trends, it might be totally possible that bringing up these sensitive topics is possible in 10 years. I personally think that those sexism and prejudiced minorities based arguments might be anachronism in quite near future. When cultural taboos are dissolved, all these topics wouldn't bring shame to the game anymore. So what might be can of worms at the moment, might not be so in the future.
Even though I don't like it, I have to admit, all games have to fit themselves into some kind of political/cultural paradigm. And when they don't, it's going to get negative attention. But we are living in age where these paradigms are changing in extreme rate, so we can only speculate what's going to be in the near future. And we shouldn't take ourselves so seriously here, because at the moment game needs more basic mechanics like magic, law and economics which is going to take time.