I think "Horizon Zero Dawn" is yet another Marxist metaphor, except with Frankfurt School elements added to it. Unlike most video game writing though, Horizon's is subtle enough that I suspect most people will breeze through it and not even make the connection. That almost makes it worst honestly, because of the subconscious normalization of SJW values. Consider:
An evil Capitalist corporation destroys the environment. The leader of the company is a white male. A woman creates an artificial intelligence program which uses top-down Communist-style central planning to terraform the new environment. Most of the leads in the AI development are women, including a hijab-wearing Muslim who wishes everyone "peace" in all of her dialogs. Meanwhile, the AI itself-- "Gaia"-- is modeled as not just a woman, but a black woman.
Think about the supporting characters too: with the exceptions of "Sun King Avad" and "Rost", the white male characters in the story are either homocidal maniacs ("Helis", Avad's father, the Hunter's Guild guy, "Nil"), or emotional basketcases ("Erend") who need to be saved by the strong, independent female characters ("Aloy", the black "Vanesha", the Asian "Talanah"). The lone black male lead character, "Sylens", is basically a copy of "Morpheus" from "The Matrix"-- so it doesn't really follow the pattern, since it had an obvious literary influence.
About "Sun King Avad" specifically, he has several lines of dialogue where he remarks that it's wrong for some people to live in the nicer town up high, versus the village down below, and that the royalty should ditch living in the palace. That damned "income inequality"! There was also that side quest where big strong female "Aloy" uses physical intimidation and threats of violence against the white male doctor to coerse him into helping some poor sick kid: "Healthcare is a right you evil whitey!"
Every character you kill through the game is a white male. I can't think of a single scene involving the death of either a black male, or a female-- the fodder are always white males if you pay close attention, as are the non-robot boss fights. The game also has several instances of homosexual characters, and frequently tosses in lots of interracial relationships in side quests.
The game is positively sprawling, so maybe there are exceptions to the above which I'm just not remembering. I may have gotten ambushed once by fodder thugs, and one of them may have been female-- I'm not totally sure. But on the flip side, there is probably lots of additional stuff following the pattern above, which I'm forgetting.
I'm a Martin Luther King Jr "color blind" person: my character and artistic choices in game design would be dictated by what would make for the best game, or what would deliver the most thematic cohesiveness: the art itself would drive things. So to me it's truly a bizzaro-land "Twilight Zone" world we live in where people designing video games of all things are sitting down with big spreadsheets making sure the skin color of the characters serves a specific political message, or meets some kind of quota, or where the whole thing is designed to not upset this group or that group-- the actual art of it takes a back seat.