I've never understood developers who refuse to give straight answers. Once the game is done all the information will be out there, and there may even be walkthroughs and mods. So, avoiding answers now doesn't matter in the long run it just makes people wonder and then act without all the information. You can keep specifics to a minimum but giving the context (at least some of it) of the beast stuff isn't a spoiler any more than announcing beast stuff at all is. For example, with the incest, we know it is there, we know there is only one character on the island we are related to (Baring some twist), so we know the "what," and the "who," but we don't know the "why," "when," or "how," yet. So there is still plenty to learn and play to see. In the same way, a little extra "who," or "how," to go with the "what," of the beast stuff wouldn't be a spoiler, it would only help get people excited for, or help them to avoid, the game if they had a little more info.
Is it a punishment for losing a fight, is it based around the MC or the girls with the beasts, is it just because there might be beast on beast at some point (like the MC finds an animal den and can see some stuff), is it some supernatural thing or mystery of the island and we will learn more but we can play without fear of suddenly having one of the girls say, "Hey, is it cool if I bang that animal?" Because a girl who wants to have sex with an animal is different from a girl who gets raped by an animal because the Mc loses a fight. That is still dumb and a waste of time, sure, since it only punishes people who dislike that content and rewards failure and not completing the game properly for those who like it... and if it doesn't involve the girls at all but the Mc either getting "punished" for losing or some transformation or seeing beasts together type thing then... that would actually be a big load off of a lot of people's minds. None of this would be a spoiler really, because you've already said it is in, so it is already "spoiled" in that sense anyway. A clear answer would simply turn negative anticipation and uncertainty into either positive anticipation or knowledge that this game may not be for some folks... and those both only help the game.
In fairness, maybe the dev just doesn't come here often and hasn't seen mine or other's posts about it. But it seems like an odd thing to be silent about.