Anyway, the terra maps obviously build on the classical understanding of the 'discovery' of America, but this is not a problem of racism but of game mechanics in that there's no middle ground between barbarian and flat out civilization.
Many goats gotten in this thread. So as an experiment, I'm going to foolishly try revisiting the point (as I understood it) of the original post in a way that gets no goats.
There are no actual races in the game, and no actual racism; it's just a game.
Keeping that firmly in mind, the terra map is highly suggestive of the historical colonization of the new world. It also suggests a certain vision of that colonization, i.e., "the classical understanding of the 'discovery' of America". This understanding was intrinsically joined to a racist discourse in which natives of the Americas were not viewed as possessing the same natural rights as their European colonizers. Since these commonly-termed "savages" had no natural right to property or sovereignty, they and the land that housed them were legally and in good conscience free for the taking. The claiming by discovery of vast tracts of land went hand in hand with a depiction of the Americas as sparsely inhabited. Estimates vary, but William Denevan for instance puts 57 million or about 10% of world population in the Americas in 1492 (though of course the population fell sharply from there).
So it isn't unreasonable to see the terra map's depiction of new world natives (a smattering of barbarians amid all that free land) as suggestive of---which does not mean identical with---a distorted and racist worldview that sufficed to justify a prolonged process of forced displacement and genocide.
There are problems with any historical analogy you draw with this game, this one included; still, as an ostensibly historical simulation, the game invites them.
This analogy is there to be drawn; am I offended by it? No. More to the point, am I offended by someone pointing it out? No. Would I be sticking up for Native Americans by being offended by it? No. Do I think someone who plays a terra map is racist? No. Do I play them myself? No, but only because they are not fun.