Don't Cuban-Americans (the dominant Hispanic group in Florida) and Mexican-Americans see themselves as 'different'. That is, they care less about the 'Hispanic' label, but care more about the Nation prefix.
I grant you, its abominable that we should have ever let the social engineers (leftists) divide us into hyphenated Americans - in their attempt to divide and conquer and enslave this Nation - but given the hyphens exist, I'd think he'd be trying to pick up Cuban-American votes in Florida by going after Rubio, or someone (since its Romney, maybe he'd go after Desi Arnez).
It seems to follow more of a regional than national, I have a Puerto Rican friend who only corrects you if you call her Cuban, but gets downright mad if you said she was Mexican.