The factors that lead to Hispanics not wanting to vote for a Black candidate just simply do not apply to Puerto Rico to the degree that they do on the mainland. There never was in Puerto Rico itself the efforts to play black against brown tension that caused that to happen on the mainland. There will be some of that thanks to Puerto Ricans who moved to mainland and then either went back or influenced the opinions of those who stayed behind, but it won't be as much of a factor as it was in the southwest.
The same effect, though, seems pretty strong in rural areas with no black population to speak of. Is this really anti-black prejudice, or more pro-Clinton sentiment? And could that transfer over to Puerto Rico?
The important thing to remember is that PR doesn't really have the "fond memories" of a Clinton presidency that the US, including places like rural Texas, does. Yes, I'm sure they thought he was okay, but PR is largely unaffected by US politics.
Incidentally, long-settled Hispanics, as in New Mexico, liked Obama, which suggests that it is the recent immigrant status that makes Hispanics like Clinton (whether for trust reasons, racial reasons or whatever). Puerto Rican Hispanics are obviously not recent immigrants.
