Ways you can call out Astarion, incomplete and abridged version:
- take vengeance for his bite attack by staking him on the spot
- give him to Gandrel
- forbid him from biting anyone else (starvation)
- tell him off for trying to bite you
- punch him for trying to bite you and/or having killed you
- criticise him for hiding his vampirism from you
- kill him after ascension. Companions will question this, example response to Minthy: "he's become a monster", M: "maybe a monster is what we need right now"
--> common factor: extreme responses
- break up with him. Be questioned by Astarion at length, get to criticise him and his behaviour FINALLY in multiple scenes (easy to find on YouTube).
Ways you cannot call out Astarion:
- tell him he's a psychopath in Act 1
- explain the concept of boundaries in Act 1
- denounce multiple offhanded remarks
- have a talk about being a victim of sexual violence and how it impacts his behaviour outside romance
Conclusion: most in game handling of Astarion comes down to extreme physical violence or starvation. Until late Act 2 to Act 3, you are not meant to have deeper conversations and shows of trust. High approval is especially important to get anything out of him, as are optional encounters. Most of Astarion's depth as a character is easy to miss on accident. Like most companions, you do not get to have some heart to heart moments without them trying to get into your pants (unfortunately). Most of the opportunity to renounce him without abandoning him is romance-gated. If you want to "teach" this terrible creature, a soft touch goes further than shouting. The game nonetheless only gives you easy to miss chances to work with him.
As for the option to just shout at him in Act 1, no doubt some players would find it very satisfying. As for my own view, I've already said it: if you can't handle him without frustration, don't recruit him. Just kill him. You are not obligated to put up with NPCs bullshit. You can walk away.
Ironically, the actual Astarion lovers would agree with you more than me since, it's become a popular point that the game either:
A) portrays you of overly tolerant of his behaviour unless you show a not so mild response (earning high disapproval -- there is no respectfully disagree until Act 3).
B) if he's romanced, this impression can get flipped and the game "aggressively portrays you as a victim" (I would say you *are* a victim, but that is how people feel).
