Probably a big “it depends”. Being racist when the only obvious difference between two people is the skin color (e.g. middle class white and black people in the US, you often can’t even tell by the name) is quite extreme, but what if there are some differences? Many groups that racists hate can have noticeable accents or smell different due to different dietary habits.

Even when its just black vs. white in the US context, apparently many blind people still react differently depending on someone’s race: npr.org/…/studying-how-the-blind-perceive-race