CALLED IT! They specifically cite PC goblins are humanoids, not fey. Ditto Githyanki PCs aren't aberrations. They are different types from the monster types.
But they will make new pc species that aren't humanoids.
Humanoid feels like a category error at this point. It's trying to be a creature type like the rest when really it's half creature type, half meta type for certain kinds of NPCs (and PCs) under the very old assumption of "humanoid = person" and "non-humanoid = monster" that the game had
almost outgrown ("NPC" is now even explicitly a subcategory of "monster" in the rules glossary, which I like as a change). I almost wish they replaced it with a "sapient" tag (or just an INT threshold, which some things already use in a similar manner) for those particular meta uses, while leaving the creature type relevant to the other rules like "Hold Person" targeting.
How does a Githyanki PC, say, born and raised in Creche K'liir/Stardock but briefly roaming the Forgotten Realms as the begrudging temporary ally of an adventurer party hunting down a mindflayer colony cease to be an aberration for the duration of the adventure? Why doesn't the magical humanoidification aura affect any other Githyanki NPCs planet-side? I don't want these to be questions the game mechanics are asking of themselves and the narrative just because "humanoid" needs to do two different, sometimes contradictory things.
The trick is to stop thinking of the stat block as the only expression of a creature idea.
I agree with this, but the reasoning given for this dichotomy (differing backgrounds) was a bit incongruous to what's actually going on from the players' perspective. If it was actually respecting different backgrounds as opposed to an inherent nature of the being, whether or not the goblin PC was a fey would be the player's decision, but players are not given a framework for that at all.
I would like to see the MM explicitly suggest that the humanoid type
also isn't the only expression of a given playable species idea - even just a single sentence somewhere explicitly allowing flexibility with the humanoid type would fix a lot of it - but I doubt it will. Being specific about "PC-ness" in flavor like this results in bizarre inconsistencies for very little gameplay impact besides... reducing flavor wherever that impact happens to a PC. A PC being immune to Hold Person isn't the end of the world. It's just a label 90% of the time, why must it be so inflexible and inconsistent despite having no rules of its own?
I know the DM's ability to change this is implicit, but RAW in a core book is extremely important to new and prospective players to a point that should probably be discouraged explicitly much more often than it is. The DMG's barebones "use whatever stat block you want as long as you
don't change size or creature type" NPC/monster creation rules are disappointing to me in that regard (it doesn't even suggest thinking about different movement speed/types).
Is that the 2024 explanation for aberration NPC gith and humanoid PC gith? That the latter are a variant that was raised in the Material Plane instead of the Astral?
Githyanki are a bit of a problem for their explanation because in Forgotten Realms lore (including an explicit mention in the 2024 DMG in the planes section - it's the second paragraph on page 184), they're
all hatched and raised outside the Astral Plane because they don't age in the Astral (so the eggs don't hatch and the kids don't grow if they stay there).