Valve has decided to allow everything on Steam (unless it's illegal) and give users tools to avoid games they don't like.
So we ended up going back to one of the principles in the forefront of our minds when we started Steam, and more recently as we worked on Steam Direct to open up the Store to many more developers: Valve shouldn't be the ones deciding this. If you're a player, we shouldn't be choosing for you what content you can or can't buy. If you're a developer, we shouldn't be choosing what content you're allowed to create. Those choices should be yours to make. Our role should be to provide systems and tools to support your efforts to make these choices for yourself, and to help you do it in a way that makes you feel comfortable.