Those are major details worth showing in the show.

> GoT already showed Black and Brown people in positions of power.

GoT is after HotD and we are specifically talking about Westeros PRIOR to GoT.

Speaking of GR Martin on being asked about Asians (which I also had issue with randomly seeing so many Asians in Westeros without any explation) from the WSJ : https://www.wsj.com/articles/BL-SEB-82711

"Well, Westeros is the fantasy analogue of the British Isles in its world, so it is a long long way from the Asia analogue. There weren't a lot of Asians in Yorkish England either."

..... so yeah. who else wants to try again with their own made up answers that apparently whole more weight than the creator of the show which you both just tried to use as proof and now look stupid.