You don't even know the story.
It doesn't matter what the story was but it seems to me like brake of rules.
It's not racist if you say it as a joke
It's still racist even as a joke, stuff like that is usually muted immediately is there's mod online on server. They got lucky, we're pretty lenient when it comes to stuff like that but come on, this one isn't even funny, it's just being offensive for the sake of being offensive.