The content doesn't need to be "justified"; people are free to express themselves as they like, in art and otherwise. The warnings are only there to make sure people who would be negatively affected by it know to stay away.
The unnecessarily detailed rape scenes were pretty good, I thought. The game is short and linear, but it's just a prototype after all; in my opinion, it's a good game for what it is.
I'm personally not offended by the criticisms themselves, but I think the "what's wrong with you" takes are uncalled for. People have their kinks, it's fine, no big deal. You don't share them, that's also fine, again no big deal.
(I don't particularly like Daniel, though. He's not my type. But the scenario is hot.)