Thats the thing in General is that the Latin American countries are not unified as one race as people think and there history is generally a little bit different than the US. It's like most Americans speak English as our default language but that has to do with the history of the British colonizing the eastern part of the United States of course regions spoke French as well in the Louisiana purchase and Florida was originally Spanish but over time so those lands were purchased, the settlers decided to speak English by default including immigrants, but that doesn't make all Americans of British or English descent.
Latin America historically the Spanish conquistadors did not bring any women and generally took native wives , conquistadors were generally thought to have been made up of remnants of moors, criminals, Sephardic, etc. over time as the Spanish empire took over before independence of those countries, they split the territory with the Portuguese to the east which had Brazil and of course the Hispanics from Spain to the west and created caste like systems, the pure spaniards which in Mexico are called criollos, castizas which were 75 percent white 25 percent indigenous, mestizos which can either be a mix of indigenous and white, in South America mestizos could also be white and black or something else, and full blood indigenous. Generally the more white you were the higher up in society you were, this is true of most of Latin America, due to shortage of workers since a large number of pure indigenous were wiped out, many of the countries imported black slaves. This is evident in many countries such as the mosquito coast of Nicaragua, the northern coast, pacific coast and island of San andres in Colombia, Brazil, and Venezuela, even the Caribbean islands would lead as a good example.
What's strange is once you get into Peru, Bolivia, Paraguay, chile, the black population literally doesn't exist, Bolivia and Peru and nearly completely indigenous, and in most cases speak their own indigenous languages yet the us would consider them Hispanic for census purposes.
Uruguay and Argentina have a but of a unique history as well, I think over time certain ethnic groups just became dominant in those regions due to a history of immigration.
Infact there has been a very large scale immigration to many of those countries such as Germans, French, Jews, Russians, Arabs, levantines, Italians, even Americans but over time they assimilated into those countries and spoke Spanish.
What is funny is that people ask my wife where she is from and they ask her what part of Mexico that is, and she has to correct them that colombia is a independent country, someone else made a statement that bogota is very hot because it's close to the equator, and we had to correct them that bogota is cold and in the mountains.