Flood gate arguments are a red herring logical fallacy.
To put it in another way, where does the developer have to draw the line with anyone's moral sensibilities? These are subjective to each person, and not universally objective. For example, what if a person demanded females to have covered faces, or no interracial relationships, or no this or that or the other thing.
My answer to that question is, the developers should go with their gut feeling, and not play to the whims of everyone's sensibilities. That's free speech in action. As long as it fits in with the lore, and they feel it adds to the gameplay why would it bother you? Now I also don't think they should have it just to be politically polite.
If something in the game offends you, don't buy it, or mod it out yourself. Don't go demanding censorship so that you don't, god forbid, see something you're offended by. Don't try to push your moral qualms on people who obviously don't think exactly the same way you do.
And it sickens me when people compare something non-violent, mutual, which has no effect on you or your life, or anyone elses who's not involved, to things like rape, killing, and child molestation. They are clearly completely different things, completely different levels, and one group is completely justifiable, while the other one is just plain prejudice.
Again, they'll have it in the game if they feel it has a purpose. Get over it.