You are sort of starting to get it.
This entire exercise was predicated on looking at it from the perspective of an evil character that values strength and power over other considerations. A character that would look at the weak being destroyed as part of the natural order of things and even from their perspective as an ultimate good.
Both Lae'zel and Astarion would look at things like that.
You miss the point yet again. Astarion is the only one interested in the absolute cult not because he thinks the goblins strong, but because without the tadpole powers he'd be compelled to return to Cazador and be enslaved. It is about the risk vs. reward for him.
As for Lae'zel, why would she be impressed by those weak enough to fall for a ghaik deception? Githyanki see that as a sign of weakness. And she isn't the only one; Nere will leave the absolute cult in disgust if you convince him it's a mind flayer plot.
It's like the evil characters you describe completely ignore that they have a tadpole in their head and what that means.
