I always thought it was people from Latin America that were descended from people of those countries, but it's hardly easy to trace that anyway. Equally, I don't understand the difference between Latino and Hispanic. I always thought those demographics were more or less the same.
In answer to the OP, I think it stems to how the slave trade operated in the US compared to other countries. Although whether this is actually the case I don't know. Coming from the UK, bizarrely I'd say most Brits (including me) know more about the US slave trade than our own. Hard to say but in the Uk the main social conflict always seems to be more rich v poor than in the US where it's more centres around race.
From what I know, Hispanic refers to Spain, Hispanic America would be countries in America that were ones ruled by Spain. Hispanic could also refer to Portugal as once Hispania was the whole Iberian Peninsula but that would be reaching as I think they refer themselves as Lusitanos and you could call them both Iberian.
Latin people could be from europe or america. EuroLatin countries would be countries like Italy, France, Spain and Portugal. Latin America would be countries with culture/languaje derived from those.
Anyway, it seems like US uses Latino to refer to people which have ties to countries in Latinamerica and Hispanic as the same (related to countries instead of a racial thing)
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