Mmmmmm...waffles!
Most white people are stupid, (don't worry I'm white, I can say that)
look at the character descriptions form Left 4 Dead
Francis, a stereotypical biker
Bill, a Vietnam Veteran
Zoey, a university student
Louis, a black guy
white people think a race is a character trait
so, if a lead is already a complex person adding a race will make him, or her, too complex for the average white audience to understand.
it's not a conscience choice, I promise
I am a white guy who writes stories and I initially imagine all my characters as white
I'm not proud of it, it just happens. I have to really think about changing them later on.
and whitewash isn't exclusively American.
Look at Anime, which comes from Japan.
all those characters look like white people too
so don't blame Hollywood, blame white people, they can't relate to anyone but them selves.
I have another example form a video game
in Dragon Age Origins I made a black human noble. and both my parents, and brother where super white. just how close to the family was Duncan anyway?