Well, maybe some players are not into that, the same way some are against dating multiple partners. In the game you literally kidnap this creatures from their habitat, then throw them in jail and visit them in order to take advantage of their lonely horny state. If on top of that you put them to work for you just because you can, it kinda sounds like slavery to me. Definitively doesn't sound like spa treatment. But hey, it's just a game and it can be played however you want. That's the hole point.