My God, Hispanics have a genetic heritage that is Indian and Spanish mix. Africans re referred to as Africans because their genetics show African features. There is the occasional White African but that is quite rare and when we say African we mean someone with African genetics in them.
Hispanics that are not of Indian, Spanish or mixed Indian-Spanish genetics are rare as hens' teeth although they do exist.
When we say Japanese we immediately think of Japanese genetics.
When we say Korean we immediately think of Korean genetics.
When we say Polish we immediately think of someone with slavic genetics.
There are a few countries where this may not be true but for Hispanics and Africans we do think of their genetics.