Well I don't hate him, I really like Alistair. But when you think about it, he is clearly letting YOU sacrifice against the Archdemon, right? and leaving, just like this?
He should be happy that we conscript Loghain, because like this we can send him instead of us to sacrifice against the Archdemon.
I totally understand why Alistair is angry, why he doesn't want to have Loghain as a brother-in-arms, but I regret that the choice we have is "everything or nothing" "kill him or I leave you". It means that his blind hate for Loghain is stronger than the love he has for the romanced warden.
(if you have a low approval with Alistair and no romance, I can understand that he leaves, even if he STILL avoids his duty as a warden and leaves you in the ****)
(They should have put an evil choice where you could romance Loghain after Alistair dumps you, then there would be a real reason why Alistair spends years being a drunk pathetic guy spending his days in a tavern
) you know, the "evil path".
He was written this way to be human. There comes a 'breaking point' for people, where no matter what you do, there's no convincing them of your PoV. For Alistair it's Loghain. In his mind you are choosing Loghain over him, betraying him. From his PoV, he can't understand why someone he loves would choose another man over him, and of all people it's the man who's spent the entire game trying to kill you and hindered your efforts to deal with the Blight. And if he loves you, when you reach the Archdemon and he knows you will die, he won't let you sacrifice yourself, you can't talk him into it. At all. So he's not 'abandoning you to die' to the archdemon, he's just leaving you since you chose Loghain (the man he blames for the loss of the only family, the only father, he's ever known) over him. A stupid move he later regrets immensely, but we don't always know what's best for us when we do things. This, makes him very 'human'.
If you were able to 'talk him down' or persuade him, that would be a cheesy maneuver relegating him to just stupid programming. "Well I can walk all over his character, he does whatever I want, whenever I want". Now granted he is an NPC ai in a game program not a human, but that would be serious immersion blowing for me if he was that easy to convince to just 'suck it up, buttercup'. One of the aspects of SWTOR I dislike is the companions in that can gain massive amounts of disapproval but never leave the PC's. In fact, you can be a right bastard in game, pass out gifts and they love you for it. Makes them seem a lot less like real people and more like ai's.
The wardens keep secrets, even from each other. At the time of the Landsmeet, Alistair doesn't know that killing the AD requires a sacrifice. Neither does your warden. You just know you need Grey Wardens. One old man (who's shown the entire game to be an untrustworthy man who's been trying to kill you and Alistair and incompetent when it comes to darkspawn) isn't going to make that much of a difference against the Archdemon. I'm surprised that he accepts being a warden and doesn't try to kill those who recruited him. Loghain doesn't know that it requires a sacrifice, so he spends most of the Blight trying to kill you and keep out all the other wardens. I can't blame either of them for something they don't know, even if it's common knowledge you need grey wardens to kill an archdemon, neither of them know why. Blaming Alistair for that and not Loghain is applying a nasty double standard.
And romance Loghain? I'd sooner kiss a wookie 