This is not common in the gaming industry, nor is it professional, nor would it likely be legal in the United States. Given that they're in Germany, though, I'm less sure of the laws there, so I can't speak to that.

Honestly, though, even if it were common, I would still not want to work on a team like that, and not just for idealistic reasons (if you allow things like that to happen you're just letting the industry continue to be racist, sexist, etc): that behaving from a team you'd be working with would reflect poorly on your career and your future, as the explicit racism would likely also exist implicitly in performance reviews, compensation, and future recommendations.