Racism in Paradise?

At this restaurant I work at, we don't always like the tables we get. For instance, high school teenagers very rarely tip. Most of the time, we prefer not to get them, the same goes for elder citizens, they only tip two dollars. But this week something happened that made me sick to my stomach. One waitress actually refused to wait on a table, and avoided them at all cost because of the color of their skin. And it's sad, because these customers knew why they were being disrespected. To make matters worse, we found out they had sat at their table for fifteen minutes without anyone checking on them. It doesn't excuse anything she did, but my boss did fire her because of her racism. And that kind of makes me feel better.