JFC, no-one is dragging Astarion to the brothel against his will. Depending on what stage his personal quest and romance is at, he'll decline sex. You don't even have the option to persuade him into it like you do with Gale. If he does accept, then he consents to a scene that he wasn't ready for, and the only issue that I have with the whole situation, is that your character should have had the option of stopping the scene when they noticed he wasn't okay, but you don't. This whole game is actually awful about aftercare, but that's a personal peeve of mine that not everyone shares.
I personally think it's obvious that a priori one should not do that to him, besides Astarion often hides his feelings under a mask, but really, if it turns out that the scene can't even be stopped (it's harder to tell on video), as you say, then it's also cruel to the player, there's no way to even correct the mistake. If it was possible to stop, it might still make some sense, not just a brutal scene for the sake of the scene itself.
