I strongly disagree with the statement that the same approvals don't make sense — they definitely make sense to me. And not just for me. As Neil said, Ascended Astarion and Spawn are only different in circumstance and level of power. They are the same person, not two different ones. Ascended Astarion is not the ‘evil twin’ of the spawn. Lord did not become a soulless monster, and the spawn remains neutrally evil because it is part of his vampiric nature, not to mention his inherent personality traits.
When Stephen Rooney was asked what qualities Astarion should have to "still be him," he replied: "He has a certain appreciation for violence, I guess? A bit of a murdery streak." "He’s a vampire, he’s all about blood, and he’s all about, kind of, those darker sides of humanity." "He’s gonna stab you with a smile on his face? Well, I guess so. That’s kind of him in a nutshell. And he might apologize for it afterwards, depending on how the conversation goes. Yeah, maybe." "He’s a bit terrible consistently throughout the game; he’s awful in a whole lot of ways." Even in the good ending, when he kills the "right" people, he does it not out of moral considerations, but because it is beneficial for him in the given circumstances.
Moreover, it’s been discussed many times on the forum how problematic it is to drastically change a character long after the game’s release, when players have already formed certain perceptions. Making such changes a year after release is too much. Essentially, with every patch, we would get a different character with this approach.
The Ascended Astarion and the spawn react differently to the affair with Mizora or the evil ending, and that makes sense in my opinion. The spawn rejected power, so when Tav or the Dark Urge choose power, it feels like a betrayal to him — you convinced him to give up power, and then you took it yourself, nullifying the climax of his good path.
Ascended, on the other hand, reacts calmly to Tav's affair with Mizora because, as in the case of Halsin, he is confident in his relationship: "You are mine. No one can change that."
The spawn, however, is more insecure about the relationship, more vulnerable. In the finale, he asks twice if Tav really wants to continue their relationship. This shows that he is in a state of uncertainty throughout the game, unlike the Ascended version of himself.
I don’t see this as a mistake. I’m not against adding new content to the game, but I am against replacing existing elements that many consider canon. The same thing happened with Ascended’s kisses — the dynamic suddenly changed six months later, which is not normal.