Why are Americans very ignorant regarding the subject of race as it relates to the peoples of Latin America?

The racial population of Latin America is very diverse(Whites,Blacks,Asians,American Indians,Jews,Middle Easterrners,Mestizos,Mulattos)much the same way that the racial population of the United States of America is also very racially diverse.I often see Americans ignorantly refering to Latin Americans as a "race". For example is William Levy,Sammy Sosa,Rigoberta Menchu,Alberto Fujimori the "same" race? All of these famouse people are from Latin America.