That here was actually very civilized. Unless some stuff was deleted. I have seen a lot of trash talk from "ntr" haters in comment sections. Always funny. I sometimes look where they commented to find interesting games. Most of them complain on games that are not ntr, but rather non-harem.
The problem here is, that it seems one hater is passionate about it and goes to such extremes as to create fake accounts to additionally vote down the game.
To your question, in my opinion that is not ntr, since it is not happening to the mc. Though some content might have been changed since I last played. And the dev said that the scenes are optional. Too lazy to read the description. From what I remember the mc was hired by a cheated husband (the fat dude), to find evidence for the cheating and the mc later could join in on some punishment or watch it. So probably voyerism and threesome involving one of the women the mc can bone.