Another red/green debacle for the 15 million color blind men in America.
It's more clear on the designers blog: http://toparkornottopark.com/tagged/evolution
It's actually more than that unless you meant just the USA, not both north and south america.
If GP meant "North and South America", he would have said "the Americas" instead. I understand this is different in other languages which I imagine must be confusing and arrogant-seeming for those with English as a second language.