Yes, you can say any myriad of races were IN the world of Greyhawk, but whether they were intended as common members of adventuring parties is another thing entirely.
And I'm saying that's a factor of the edition the game was written for, not an intrinsic part of the setting. You can make the same exact arguments that dwarves should not be wizards or gnomes paladins in Greyhawk with the exact same logic. Or that sorcerers should exist at all. Greyhawk followed the game conventions of the time. Those conventions have changed. The setting should follow suit.
I think you are being a little of unfair calling my viewpoint revisionist.
It's unfortunately true. The identity of Greyhawk in the 90s was just the older and less thorough kitchen sink setting. The idea of Greyhawk being some carefully curated OSR setting built to perfectly fit the burgeoning OS movement is recontextuling the setting into something it never was (or more aptly, only was because D&D itself leaned in that direction).
You've got multiple sources from throughout Greyhawk's history backing up what I'm saying.
Nothing their specifically forbids options from beyond the PHB, only going as far as to explain the old paradigm of humans in ascension (all classes, unlimited levels), demi humans in decline (level limits, limited options, small populations, few or no major nations) and Humanoids for killing guilt free. Which was true of Faerun at the time too prior to 3e (I remember the return from Evermeet and Thunder Twins used to explain why Faerun had an influx of elves and dwarves after decades of AD&D era populations)
Yes, I think you are misunderstanding what I'm saying, or I failed to articulate myself clearly (which is more likely

). I'm not saying that these races can't or don't exist in Greyhawk, but rather the chances of them being PCs are significantly low.
Low =/= unplayable. And it's worth noting most of the humanoids you mentioned are in supplement books anyway. The 5.0 PHB had two additional species (Dragonborn and tieflings) and 5.5 added aasimar, goliath and orcs for the half-orc. Nothing there breaks the setting, and if gnomes went this long without a nation, dragonborn can do the same.
See my previous comments, especially about Living Greyhawk. Existing is different than being forced into the setting in the way Dragonborn were in Faerun for example.
Dragonborn are a good example of why continuity breaks per edition are better than RSEs. Eberron incorporated them far better than Realms did just by saying they were always there, just not in significant numbers.
Yes, these different races can, and in many cases do exist in Flanaess. However, they are not in the majority of adventuring parties and every 7th PC probably isn't a member of one these races and is most likely Human or one of the "Demihuman" races.
But that is YOUR opinion on how adventuring parities should look, not the settings. Humans are the predominant species, but that doesn't mean a kenku can't become an adventurer. It means you aren't going to meet many kenku bartenders and innkeepers. Adventurers are already pariahs from society, it would make more sense it would have more representation from marginalized groups than your local town or maybe kingdom.
Unless we're playing the "Greyhawk is so racist that an orc entering town is enough for a lynch mob" style of play. Then I don't know what to tell you but the setting needs a full restructuring.
I'll point you towards the top of this post for that. I don't think I'm a Grognard for thinking that Greyhawk is a Human-centric setting. But, it's all down to preference right? WotC can move forward and do to Flanaess* what they did to Faerun, but then I fail to see some of the point of Greyhawk and they might as well just stick it into Abeir-Toril somewhere.
If the only thing you see of value about Greyhawk is the fact you can ban a player from being an aarakroca, then I agree. If all the setting features is a ban list, then the setting is too weak to survive.
*I actually really like what WotC has done with Faerun even though I think it steals some of Khorvaire's cosmopolitan thunder.
I feel the Monsters of the Multiverse effect has been widely overblown. The 5.5 Forgotten Realms book isn't teaming with kenku villages and tabaxi nations. Ravenloft doesn't have a single humanoid darklord that isn't human in origin. WotC isn't pushing some hidden agenda, it's just giving players and DMs options beyond the Tolkien Seven based on what else is popular. But it reinforces a lot of bad takes on modern D&D and the notion that OS play is the correct way to play. And Greyhawk has been retroactively made the poster child for that.