I always thought of the pokemon universe as a unified race. That being said, as many have stated before me, the games are made in Japan. Japan is in Asia, where there are not that many black people. The artwork for the main characters is supposed to be asian. However with the games coming over to the USA and other countries that have a high number of whites, we envision the characters as white due to the light tone of the characters skin and the lack of asian features. The eyes of the characters are not squinted and small, because of this we see them as a race in our own country similar to the artwork.
Heck the only people in pokemon that could be called not asian is Lt. Surge and Dahlia. But even then I consider her to be more Puerto Rican or Coluumbian, something south of Texas. (This may be ignorant so I apologize beforehand, but I have never seen a black person with blue eyes).
However to avoid the issue, customization of the main character would be helpful.