Lucas said:
Why do all these people are obsessed?...What are the motives for that?
Well, the motives are that those countries are in AMERICA TOO!!
Not really. Those countries are in South America. It simply does not make sense in
English to say they are in America. This is because (thanks to common usage of the term throughout the English speaking world) the United States "owns" the title "America" as a singular country.
I have lived south of the Rio Grande for ten years. While I was living in Mexico I always referred to myself as Norte Americano and this was the correct term to use there (as opposed to just saying I was an Americano). Ironically, Mexico is technically in North America, but Mexicans do NOT call themselves Americans (except for those lying to border control or US immigration agents). Neither do the inhabitants of Canada, Central, or South America when identifying themselves by their nationality. They may say in English, "We are Americans, too." but in the context of nationality that is misleading if not meaningless unless they are naturalized American citizens.
If they want to say "somos americanos" they are free to do so, but they simply aren't Americans the way the term is commonly used.
In the French film L'american, my high school girlfriend had the line "Everyone wants to be an American." No one in the world thought she was referring to the people of Colombia, Uruguay, or Argentina. I do acknowledge, however, that there are citizens of these countries who really
are obsessed with
becoming Americans.
Nonetheless, once in a while
We Are All Americans:
http://ics01.ds.leeds.ac.uk/papers/vp01.cfm?outfit=pmt&requesttimeout=500&folder=428&paper=922