I respect your opinion, but not choosing to express yourself artistically because your afraid of what someone might do really defeats the whole purpose. And it being a bestseller isn't a good argument in itself for why it should or should not include these elements in game that I agree should have them since human vices would be best displayed in a post-apocalyptic setting where there isn't any entity to try and uphold morality.
Selling the game has to come first. This is a business after all. Artistic expression needs to come after the financials. Sorry, but that's how it works.
As far as upholding morality, well, you have a point. I was reading a survivalist book, and one of the few things that made sense in it was the author's argument that, no matter what the economic condition, one can guarantee income by providing six and drugs and rock n roll. Sell your body, build a still, and learn to entertain.
There is a place in a PA game for vice. I'd argue, owever, that design resources can be better used elsewhere.