I think the issue here comes because you conflate "culture from where you hail from" to "your culture". I think the issue is that people are expected to have a specific culture and an idea of what that is, simply because they were born in a certain place. This is kinda old-world thought, it used to be like that back in the day. It is not like that any more.
Do you know what I see when I see all those Greek references? I see the stories I grew up with shone through the prism of American/British culture. It's its own thing entirely. I do not see that as me experiencing Greek culture, no, not at all, I see it as experiencing American/British culture, which borrows (not appropriates, borrows) a lot of Greek myths, cause they find em cool, which is awesome.
The thing, however, is that that is not really "my" culture at this point either, it's a new age American culture that is a melting pod. It is not being any more representational simply because it is more positive or nuanced than the snake people are. The way I see it, the American and British people just took the things from the Greek myths and tales that spoke to them, and adapted them in ways that they found cool.
No culture is owed to be found cool by American/British culture. These cultures get to decide how they feel about various world cultures and should be free to depict them in any which way they desire.
Also, the big elephant in the room is that, just because you're born in some place, that doesn't dictate your culture. My culture as a trilingual dual citizen with fluency in Japanese is vastly different than what you'd stereotype as the standard Greek culture that'd hypothetically be satisfied by their dnd depictions in the same way you'd be by a more nuanced Astec representation. My culture is actually just the culture of anime fans, gamers, fighting game players, card game players, etc. That sort of thing takes precedence over where I happened to be born at. And my culture is a mix of all of the above, adding with the elements of Greek upbringing and life in America as an adult for the past 15 years, all the while being an avid fan of Japanese pop culture and studying their cultures and music and language.
So, at the end of the day, I really don't get the feeling of representation from things that appease that stereotypical imagined Greek person's wishes, I get representation when people respect gaming and lore and canon and things like that. That is more important to my identity here. How they respect the mediums these works are made for and the culture that sprouts from them is what I actually identify the strongest with.
It's not that it's owed to us Dreiko, it's that we're customers and we're saying that we find it cool, so while Americans or British people may not, we do and we want them to be cool and also possible heroes too, like the villain stuff doesn't really bother me, it's fine to have them as villains and they're cool as that, but if me as a paying customer that wants it in the game am asking for it, why shouldn't they address this if they think it's going to sell?
It's simply fulfilling market demand, and before you go all artistic intend on me, we're talking about a game by Hasbro that has canonical Crossovers with Rick & Morty and Stranger things, that constantly retcons it's lore every time a new edition comes out and often in re-prints of old adventures so this is nothing new.
Again they retconned the Drow Elves to have a good aligned deity at some point so that there could be more Drow Elf adventurers because they are a super popular race to play.
Anyways it's cool that you view your culture that way, but things are different for me, I'm not white like you I've faced discrimination, I've seen people claim that we're lesser people just by virtue of where we were born and the colour of our skin, claim that we're dumber than white people just because of that so yeah, an accurate depiction of my ancestors is kind of important to me, after all it proves that in many ways Mayan & Aztec cultures were far more advanced than Europeans, their accomplishments in Mathematics and Astronomy are astounding and when I've visited the Pyramids I was absolutely blown away, so you know who cares, my relationship to my culture is different from how yours, it doesn't make it less valuable than yours, I'd say both ways of viewing things are perfectly fine and neither is inherently better than the other.
Anyway, at the end of the day it all comes down to market demand, if the people want to buy a product in which Orcs, Yuan-Ti, Vistani and so on are more equal to other races and more morally and culturally nuanced, that's fine, the reason why they want that shouldn't matter, at the end of the day D&D is a product and they can choose to provide the product the public is asking for if they want, if on the way they want to make political statements because they think that'll help them sell more that's fine too, almost every company does that.
Again you can claim what you want about artistic merit, but D&D has sold out for a long time, if you want something more artistic and more specific you can always buy an independently published RPG, some of them are more politically charged, depending on the game that can mean more PC than D&D or definitely not PC at all, now that's not to say that there isn't any artistic merit to D&D, there is and a lot of it, but you can't expect it to be the critical darling super-nuanced RPG when it's by all intents and purposes the blockbuster movie equivalent, which again is perfectly fine, it's just that D&D has always made sacrifices in the name of marketing, some quite bad, remember when they screwed over 3rd party content publishers because they wanted more money with 4E?
That didn't pan out well, and it costed them quite a few l beloved books and adventures, one example is the Golarion setting by Paizo, which ended up becoming Pathfinder because of that really dumb business move, also like
@Secondhand Revenant mentioned that also involved a lot of lore changes many of which weren't well received, anyways, my point is that it's a commercial product and if people are buying this, it's perfectly fine for them to sell it.