you gotta remember that Japan is a pretty homogenous. The native population (which makes up a huge percentage) is all asians with black hair. I hear that the reason anime has all these unnatural hair colors and such is because artists want to express variety in their work that they can't get in real life, thus such a style has become a norm (or it could be because the artists are reflecting the people who dye their hair, also to seem independant and varied.... don't know which became popular first). As for the caucasian skin, it's either because the anime style descended from early American cartoons, or as I've heard someone on the thread mention, it's because that skin color's easy to mix (and thus cost-effective) in paints, and even with computer technology now, that has become a norm. Either way, anime tends to showcase characters as they are, not focusing on such trivial issues as their race (their race usually being considered a fictional varient of Japanese people despite looking caucasian). The few times race variety does become an issue in anime is when the storyline involves foreigners (like with war stories and their foreign affairs), the storyline takes place in America or some country with more cultural variety, or on an even rarer occasion, a black foreigner's plopped in as a background character in order to be realistic.
Brock could be Indian or Hispanic, or Chinese due to his eyes looking as if they're closed shut.