Seems ~20% of the population are immigrants (https://en.wikipedia.org/wiki/Nuremberg#Demographics), some of the people you saw are Germans and some of them are not, but I think the main confusing part is how you mix up how someone looks and what nationality they have. I think maybe you're trying to say "white" instead, but for some reason avoided using that word?
Not sure what you are babbling about but, It's about ethnicity and not race. Plenty of third generation Turks still don't consider themselves German, then someone with black skin adopted as a child might consider themself German, it's about culture not race, we're not in last century anymore. Proportion of young people with immigrant background is high in many Westeuropean countries, if they don't integrate into society they won't be willing to defend it.