Read any standard dictionary definition of the word. Look into the etymology of the word. Hispania is the Iberian Peninsula. Spain. Hispanics are Spanish speakers.
Perhaps, then, cultural usage trumps etymology and geography.
Also, one can go to Spain and hear Castilian, to Argentina and hear Spanish with an Italian lyricism, to Chile and hear something quite different, not only in accent but in common usage. It’s easy to discern Cuban Spanish and Puerto Rican Spanish from those who speak it in the Hiberian Peninsula.. And then....there is Spanish as spoken by a Filipino.
See how far this can go?
Finis.
Latino is discernible from Anglican settlers in the New World. Hispanic culture tended to arise from those given land grant from the King of Spain.
(Latinos drive green Impalas, while Hispanics ride thoroughbred horses. ;^)