What’s the origin of the old stereotypes that describe Asians as having “yellow” skin and American Indians as having “red” skin? I’ve never seen an Asian person with even remotely yellow skin; and the only people with a reddish skin are lightskins who’ve been sunburnt.
Of course one could argue that blacks aren’t black, nor whites white, but at least I can see where the dark-light oversimplification came from. But why where people labeled “yellow” or “red”?
“Oversimplification” is the reason as you stated. Granted, nobody is pigmented the same as their racial color (even “white” albinos are more pink than white). But Asians tend to look more jaundaced than Europeans, at least those without sun exposure.
I believe some Amerinds (Indians, “Redskins”) covered themselves with a thin mud covering as a UV protectorant. This mud was slightly ruddy, and thus they were called “red”.
Besides, it makes that Sunday School song easier to sing:
Jesus loves the little children
All the children of the world
Red and yellow, black and white
They are precious in His sight
Jesus loves the little children of the world!
Skin color assignments are a method of derogation. It is easier to rationalize killing someone who is ‘different’ and therefore subhuman or not equal in some other way. Skin color has always been useful but, if that is not available, religion, mode of dress, language or customs can be used. Or even the fact that the other people live in some particular geographic region. I have long been in favor of taking out the Canadians. 
Um, AFAIK the western world has never tried to kill the chinese - not that suicidal yet perhaps…!?
Saying that tho, I seem to recall some western country failing to quash a south-east asian province some time ago…???
Um… the Boxer Rebellion?
http://www.smplanet.com/imperialism/fists.html
This threatens to become a total hijack, auliya, but after reading the link, I don’t think “tried to kill the Chinese” is an accurate description of what happened. “Exploit”, sure.