Thus, Spain and Portugal are the two original Hispanic cultures. Any culture that has Hispanic roots (i.e. most countries south of the US) is also Hispanic.
Anecdotally, a friend of mine was a first generation Spanish immigrant, and won a college scholarship aimed at Hispanic immigrants.
When he's referring to "Hispanics and African Americans" he is trying to refer to specific "racial" (insomuch as the concept exists) groups.
It might be an academic distinction to you, but it isn't to everybody. On the flip side of your example, while teaching in an inner city, I broke up a fight that started because a kid called a Haitian "African American".
It's far from an academic distinction to me, and that fight could have just as easily occurred if an African American had been called a Haitian, or any number of similar errors...