The reason for the distinctive pigmentation of Springfield's population is simple: Matt Groening wanted people to be immediately recognise The Simpsons if they were channel hopping, or (if the potential viewer somehow wasn't aware of the show) so that they'd stand out from everything else on the airwaves. Simple, right? Things get a little more complicated when you consider that referring to certain people as yellow-skinned is super racist, which is apparently the reason Burma banned The Simpsons Movie outright from being released in the country. That's in keeping with their existing policy of never showing the TV show, either. What on Earth do Burmese kids quote endlessly at one another instead of having actual conversations? Apparently the country's Motion Picture & Video Censor Board are notorious for their instance that the colours yellow and red are banned in movies, meaning that Hellboy probably fared about as well in Burmese cinemas as it did... everywhere else.
Tom Baker is the Comics Editor at WhatCulture! He's heard all the Doctor Who jokes, but not many about Randall and Hopkirk. He also blogs at http://communibearsilostate.wordpress.com/