How the hell is that racist?
In American culture, there has been a fairly large backlash regarding hairstyles towards women (and men) of African descent straightening their hair or making it more "European" for decades. Malcolm X, I believe, talked about this sort of thing.
I don't think the show was making any kind of statement on the matter. I just think Burnham adopted a Vulcan hairstyle when she was more involved in Vulcan, and now has a more natural hairstyle, because she's expressing herself more freely.
As for racism, I was taken aback when I thought Connolly said he was qualified because he was better than his Asian roommate. Turns out he said "Caitian roommate", which I guess is still racist, but fictional racism.