Hence why "avoidable" tags wouldn't solve the issue, people would still be asking if the avoidable means X,Y or Z and so on.
The dev here for instance made it so most content from the game intro is fully modular but even then people manage to complain about screenshots, tags or other stuff.
This game is great and everything that isn't essential to the story is avoidable, most people are just playing the game, a few other are complaining without even trying it, most of which will come crawling back in the future as the game grows without ever admitting they misjudged the content for relying on opinions of people that haven't even played the game, instead of just checking it themselves.
Eh, from what I have seen its pretty much become standard for definitions be:
Avoidable = Never happened, not cannon if you don't choose it.
Skippable = Still happened, still cannon but you don't have to watch.
Most, if not all the people who have issues with certain types of sexual content will want things to be avoidable, not skippable. If you can story wise, its always good idea to make anything objectionable avoidable.
Though obviously if your main theme is something divisive then you're just going to have to tell people up front and let them decide if its for them or not.
E.X. 1: You want to include a scene where the MC can rape a character, making it avoidable is better as that's pretty damn divisive but might not be crucial to your story, so avoidable is a good call rather then skippable.
E.X. 2: You want the premise of your game to be cucking the main character, then there is no amount of avoidable that can salvage that for people not into cucking so you'll have to tell people, sorry, this is not for you.
Imo, this is how it should be for all games.
If you have a fetish central to your story, tell people its an XYZ type of game and they can either enjoy or move on.
If you have a fetish you just want to include for sexy content, make it completely avoidable so people can pick and choose per their preferences so you don't force a fetish onto anyone. Not everyone is going to have the same types of fetishes and its important to let people keep or expand their boundaries as they like.
Also, by no means does this mean you HAVE to offer them something comparable if they choose not to indulge, especially if the fetish is on brand for your VN's theme. It's their choice to avoid or not but if you're going to include a bunch of ancillary fetishes for sexy content, why not include an either or?
But that's just my opinion. Its... an interesting choice to start off another BDSM fetish game with a MFM relationship. Obviously the Dev doesn't see that type of relationship as a problem judging by his reaction to the feedback so will be interesting to see how the rest of the game goes.
As a side note, the transition on the cell door when first captured was slick as hell and I appreciate that bit of dev craft.