It makes me feel unccomfortable, so I don't like it. You don't feel the same, so you don't care. It isn't about morality or anything, I just find the idea uncomfortable. And yes, if this was real life I would really have nothing to say against them doing stuff since I'm not being particularly faithful myself, but this is a game. In games a lot of this are altered so it's more fun. How many harems in games would have worked out in real life? Almost none. But since they are games we can look past it. This is the same concept, A little less realistic maybe, but more enjoyable. Especially since, if it's a harem, it would be cheating. Maybe I just have a harder time seperating my emotions from sex. Maybe you are just into NTR.
What right do you have to mock me if you don't even understand me?