Today, most if not all Starbucks locations in the United States will close early for what is being called "implicit bias training". In short, they had a bit of a media meltdown after two black men were arrested at a Seattle location for doing nothing. Literally, their crime was they were doing nothing when they should've been doing something (namely, purchasing a drink). From the way I have heard the story, and accounts vary as they always do, these men had the cops called on them after asking to use the bathroom and hanging around the shop after being asked to buy something or leave.
This is a much, much larger issue than these two black men and one impatient barista. This is an issue of what is known as "implicit bias", and it stems from a long and troubled history of racism in our country. Implicit bias is similar to making assumptions based on appearances, or stereotypes based on group identity. If I, a white woman, started a fight with a black woman, a passerby might assume that the African-American woman was the perpetrator because I, a fair skinned woman, look less intimidating and less likely to pick a fight.
This is so much of a deeper problem and I am barely brushing the surface here, but the point remains: people make assumptions based on skin color, and those assumptions favor lighter skinned or white-passing individuals.