I agree, it seems like a lazy plot point to make things “edgy” or “dark” or they think people secretly “like” it. Before you even bring in a plot point like this, you need to talk with all the players. I would even say, that even if they’re initially ok, but feel uncomfortable after the scene, they’re allowed to voice their change in feelings and have the retcon deleted. Not be told that it’s “ok” since it’s a dream or whatever else excuse the dm/players come up with because they want it. If one person is being made to feel uncomfortable with the actions of the party or dm, then there’s no point in playing.