The rest of the alignment talk is getting off topic so I'll spoiler it
...so your argument is that even a single non-good action prevents a creature from being good, ever? That's not how alignment works. An overall lawful good character can slip up a few times and be somewhat cruel or not fully follow their code, as long as they overall stay lawfully good (and ideally repent/feel remorse). The Lawful-Chaotic and Good-Evil axes are spectrums.
I don't think moral relativism is the term you're looking for here. Moral Relativism would state something like "your good is my evil, and thus who really knows what is truly good vs evil?" However, this isn't applicable as D&D has an Absolute Reference Frame as *defined* by the Gods and the Planes of Good/Evil.
The 5e spell "Protection from evil and good" is an example of how WotC is already removing alignment from D&D; you can't use it as an example of how older editions of D&D did alignment wrong.
Idk, at the very least the contrast between your views and my understanding of alignment are an indication that it should be more well-defined by WotC, not that it should be scrapped.
I did mean moral relativism. What makes something 'evil' enough that there is no coming back to the 'good' side is different for different tables (cultures/groups/whatevers). What number of innocents murdered flips the switch from good to neutral to evil. For some people 1 is enough to stain you forever regardless of your reasons, for others killings done for 'the greater good' can outweigh a number of murders, to another it is simple math if you have saved more people than killed, then you are on the good scale. My argument is that there is no absolute authority on that line, nor what it takes to cross back the other way.
Short of listing a large number of representative actions and attributing point scores to each of them on the goodness and lawfulness scale, there is no way for there to be an 'objective' right and wrong in a game. And there are very few companies that will do that for a game with as much freedom involved as there is in BG3. Owlcat could do it because they had pretty simple choices and their world wasn't very interactive. Meanwhile, Bethesda games, which are arguably make the most 'freedom of choice' based games of any other company, do a shit job of it.
As we've seen in other games, as soon as you start making some chests "owned" by different groups and others not marked you are defining a moral point system, and things get messy real quick. Is it lawful to loot a body if you killed them in the name of the law, or must you turn it in to the authorities? What if it was self defense, should you get their stuff or should their surviving dependents? What about if you steal from some thieves? Is it moral to keep their loot, even knowing that it is stolen, or is it your moral imperative to hunt down each of their victims and return their goods?
How should any of those choices affect gameplay? How many points are each worth on the scales? How many donations to a temple does it take to reset an alignment?
So no, I don't think alignment is useful for anything other than a basic starting point along the lines of 'yeah that guy mostly follows the rules, but tends to use it to screw other people over' or 'that guy does his best to help everyone, but he keeps breaking laws to do it' communicated to the player by someone who they may or may not trust to be accurate (knowing everyone has biases and their own motivations). After that initial introduction, it is up to the player to make the call based on their observations of the NPCs actions.
