One: I have answered you specifically many times, over many threads, over many months, but sure we can go over your list again.
Two: As noted, the fluff/lore, certainly points to an expectation in the MM irrespective to the existence of a Chaotic Evil, or Typically Chaotic Evil, classification. Again however, the topic is Alignment, not supportive writing regarding setting lore. That certainly would be a lot of work to rewrite.
So now, lets retread the topics you and I personally, directly, have discussed multiple times. If I miss a question, its not intentional, I was finishing cooking lunch and didnt want it to burn.
Typically, when I've asked you these questions, you've ignored them...
Its a setting specific question, and the MM and Volos (books people commonly take exception with, but certainly not an exhaustive list of the problematic material Wizard's has published) have set things that way. Please also note, the MM objectively, specifically, and clearly, states there is no 'ALWAYS' and its up to the DM's discretion to follow a suggested Alignment.
And also please note that the MM only provides information that enforces the idea that a monster is evil. As
I've said numerous times, if you want to play a particular monster in a different alignment, there's nothing in any of the book that supports you. Even though the MM says you can, every bit of information given for a monster fights against that option. That makes it
not setting specific.
I'll give an example: harpies. Chaotic Evil. Their lore says Divine Curse, Harpy Song, Sadistic Cowards, and Gruesome Collectors. We can ignore Harpy Song for the moment, because that's just about their ability. It's the other three bits of lore that are important. This is in the Monster Manual, which is supposed to be setting agnostic. I should be able to use harpies in any official setting and any setting I homebrew.
If I make them not CE, then Sadistic Cowards and Gruesome Collectors stop making much sense. If I don't want harpies to have been created because an elf got angry and her evil curse backfired on her, then Divine Curse doesn't make sense. So anywhere from half to three-quarters of the monster entry is unusable, simply because I don't want them to be Evil. That puts a
lot of effort on me to make them useful, a lot more than simply ignoring a monster.
Any change to alignment is automatically a change to lore. If I want to have D&D harpies, as a species, that aren't evil, I need to
show that they're not evil, not merely
tell the players that.
Now compare to
Level Up's treatment of harpies, which doesn't give harpies an alignment. Their lore includes Luring and Tracking, Artistic and Scholarly Inclination, and Nature's Intermediary. They hold grudges, make for good historians because of a rich oral history, and can predict the weather by tracking air currents. If you want
your harpies to be Always Evil Kill On Sight, then literally the only thing you need to do is not have them play nicely with PC races. You can even keep the good historians bit and say they simply don't share their knowledge!
Ultimately though, much of the game is based on combat, the rules are certainly slanted towards combat, and as the game has been for decades (Tasha's being the point of direction change in my view) been that way, they (WotC) decided to give players and DM's creatures to fight without burdening the DM's with justification. As you say its a lot of work to write up the lore!
"You're attacked by vicious bandits who happen to be goblins" is no more difficult than "You're attacked by goblins."
And "you enter the lair of the vicious bandits to kill them" is heaps better than "you enter the lair of the goblins to kill them," because then the players and DM have to justify killing children and other non-combatants. Do your PCs kill them because they will grow up to be Evil goblins? Do they leave them alone to starve to death on their own, which should alter the PC's alignment? At least with a lair of vicious bandits who are goblins, you can logically write it so that there
are no children or non-combatants there, or if there are, they're unwilling but have no ability to leave.
Although personally, I don't think DM laziness or lack of creativity is a good enough reason to include alignments.
I believe I covered this, but I dont want to be accused of skipping a question. Yes, the lore would indicate monsters are evil. It seems (to actually be on topic) that the lore around Black Robes ALSO points to them being either overwhelmingly evil, or completely evil as an organization. This would seem to make sense since you know, EVIL God, of EVIL Magic, being the patron of this NOT EVIL group...but....
I never asked about the Black Robes, and while I think the idea of alignment-restricted mage groups is stupid for a wide variety of reasons, it's an organization one
chooses to join, not a race one is born into. Likewise, one
chooses to be a vicious bandit.
Because, even a 'typically' rider, informs on the setting in question. Even Eberron, comes with assumptions around the specific cultures, the specific creatures, and monsters no?
Keith Baker said that D&D came with certain expectations he had to include in Eberron. While he didn't elaborate, I would not be surprised if that meant including alignment and those assumptions were things he was forced to include.
But you inadvertently made my point for me. Even in Eberron, we can't escape the idea that some races are intrinsically evil, because TSR/WotC decided that they had to have an evil alignment. Below you say "I still believe its far easier to say 'drop any assumptions you have around the NPC's or Monsters you encounter, this is a different setting'," but here you are admitting that's not the case.