1) If you are going to kill everyone, what stops you from doing it after you asked all questions? Removing the need for the spell.
This question is absurd in a D&D context.
2) "Speak with dead" isn't Larians invention. It is a DnD 5e spell. And it is one of those that are hard to implement good (hence the advertisement).
BG3 is not going to contain everything in 5E. And, many of the things that are "included" have been or will be altered significantly. So, there is quite a lot of leeway for Larian to choose if and how to implement this spell. The fact that they are doing this gives me the impression that they don't see any alignment/RP issues with killing everyone for XP.
3) Noone is forcing you to abuse this exploit to get all the XP in the game. I finished DOS2 without using it.
This is a terrible argument. I might as well just play a different game, then. It is the responsibility of the designer to make good choices and justify them. More XP is one of the central goals of characters in an RPG, especially when there are weak or nonexistent alignment concerns.
