What does my “cultural wallpaper” have to do with racism?

“Being White in America has long been treated, at least by White people, as too familiar to be of much interest. It’s been the default identity, the cultural wallpaper — something described, when described at all, using bland metaphors like milk and vanilla and codes like “cornfed” and “all-American.” Grass is green, the sky is blue and, until very recently, a product described as “nude” or “flesh-colored” probably looked like White people’s skin.” (Emily Bazelon, 2018).