The two are not equivalent. America is shorthand for the United States of. Mexico is short for Estados Unidos Mexicanos. Europe is a geographically defined continent.
If I were in Switzerland, Norway, Iceland, Serbia, Macedonia, or the Ukraine would it not be appropriate to say I was in Europe?
Well technically I think it depends on which side of Iceland you're standing. To the west you're on the North American plate and to the east it's the Eurasian plate.
Consider that the only country within the North/Central/South American land masses explicitly having America as part of its name is the United States of America. It makes a lot of sense really considering the global dominance of the USA relative to its neighbors that "America" is colloquially understood to refer to the USA, and not Canada, or Panama, or all of South America.
If I were in Switzerland, Norway, Iceland, Serbia, Macedonia, or the Ukraine would it not be appropriate to say I was in Europe?