Even optional ntr kinda taints the whole thing, especially since they normally have completely different scenes/animations aside from just dialogue changes; scenes that I, as a porn-game player, would like to see if not for them being ntr. It's like if I'm having a lovely time playing Nintendogs and the game told me "hey, you don't have to, but there's a gun over there for you if you wanna ice one of these pups. Totally optional, but you'll get a really cute sweater for the other dogs if you do." I really want the sweater, but I don't want to shoot a puppy and am frankly disgusted the game would ask me to. The porn game equivalent is "I want to see this hot scene, but I don't want it to be from the perspective of some pathetic dude helplessly watching from the sidelines. So, I don't think cramming any and every fetish into a porn game necessarily makes it better, especially for the real extreme ones not just ntr, but stuff like gore or scat. You're right that people who hate it really hate it, but if the patrons want it then I get that you can't help but oblige. I just think doing so would alienate a lot of potential players.