In Japan, where nearly everyone is Japanese, I suspect many people look at the cartoons and see Japanese people. Weird hair colors help them stand out.
http://kotaku.com/5627268/why-do-japanese-characters-look-white
It's complex.
I certainly see European-looking people in a lot of anime. But was that the intent, or am I simply assuming light hair+ fair skin= European?
And much of it is stylized, with those big eyes, so it can be hard to say for sure...
Sometimes the characters are obviously European or quasi-European, though. German or English names, blond hair, Western-style setting, etc.
And then there's futuristic stuff, where perhaps a more diverse milieu is being shown. More diverse than present-day Japan, I mean.