It seem to me that the map shown on the first post just seems to colour in NATO member countries or NATO friendly/influenced on nations. I think Argentina, Uruguay and Chile in some degree should also be considered part of the western world, a type of "Far West".
My main argument stands on the premise that to me the definition of western civilization has to be linked to a deep cultural tie between all of the constituent nations of this "civilization". To what should tie all of us together is having a Greco-Roman cultural base on which each of the respective nations have grown and evolved in their own manner. Rome is the base of all European culture which then spread all over the world due to colonialism. The areas of the world where Western Culture has best set in are North America (USA,Canada), Australia, New Zeland and the "southern cone" (Argentina, Uruguay, Chile). These countries have all embraced old world culture at some point. In the case of the south american nations, it almost became an obsession to copy Europe to distinguish ourselves from the barbarity of the rest of our continent. I, as an Argentinian, feel part of western society and am very hurt when felt left out.