To be geographically correct, it should not be refered to as "America", but people from the Nederlands refer to their country as Holland, even though it's only a province, and they call themselves Dutch, yet they are not part of Deutcshland. People from the DR call themselves Dominican and not Dominican Republicans, and people from the USA call themselves Americans. So we sometimes hear the DR refered to as "the Dominican" as USA is often called America. When we sneeze, we ask for a Kleenex, not a facial tissue. Such is life. A lot of shortcuts and abreviations that make life simpler.